Inter-Municipal Planning as a Framework for Managing Policies for Inner Areas: Insights from the Italian Context

Abstract

The socio-economic geography of the Italian territory is framed by strong imbalances in the settlement development, with consequent inequalities in terms of accessibility to essential services. These challenges are most critical in the ‘inner areas’, which are remote from metropolitan and urban centers and affected by chronic demographic decline and depopulation. Both European and national policies have relied primarily on financial interventions, often implemented with limited integration into comprehensive urban and territorial planning frameworks. Using a case study methodology, this research examines the area-based strategies of the 72 pilot areas designated under the 2014–2020 program-ming cycle of the National Strategy for Inner Areas (SNAI). The main research question guiding this study is as follows: how does economic planning intersect with territorial governance in Italy’s inner areas, and what is the specific role of local autonomies and the management of core functions, particularly in relation to urban and regional planning? Through this lens, this study proposes a conceptual reframing of the inter-municipal ad-ministrative scale as a strategic framework for promoting more effective territorial policies.

1. Introduction

The concept of “inner areas” (IAs) has been the focus of a wide scientific debate which, due to its multifaceted nature and the critical aspects attributed to it, has led to a variety of interpretations [1,2,3]. Characterized by structural conditions of peripherality and marginality in relation to the main urban centers, these areas are affected by a multidimensional pattern of territorial disparities, which include not only spatial aspects, but also political, economic, and social dimensions [4,5]. Marginality and peripherality denote forms of subordination that are difficult to quantify/spatialize [6]. Traditionally, they have been defined in terms of a lack of proximity, understood as geographical distance from a hypothetical center. Over time, this criterion has been complemented, or even replaced, by the notion of “relational distance”, which emphasizes the absence of socio-economic and political ties [7,8]. Specifically, IAs are characterized by limited access to basic services, demographic decline, and the erosion of social capital, phenomena that have been extensively documented in scientific literature [9]. In recent years, this issue has gained increasing prominence not only in academic debate, but also within European cohesion policies and the institutional agendas of Member States, reflecting the need for coordinated responses to structural challenges through the integration of different levels of governance [10].

There is a growing interest in alternative development approaches that are better equipped to address the specific characteristics of these areas, given the limited effectiveness of conventional growth-oriented policies in contexts marked by demographic and economic decline [11]. The mainstream approach to IAs introduces new perspectives for strategic and spatial planning that require overcoming traditional administrative boundaries and conceptual dichotomies between center and periphery. This approach makes it easier to define territorial policies that cover a wide range of factors, including mobility, environmental protection, and the distribution of services. Consequently, this approach offers more effective responses to contemporary challenges [12] while also fostering cooperative frameworks among the institutions responsible for territorial governance.

The EU Agenda 2030 and national strategic frameworks, both in the 2014–2020 programming cycle and the current 2021–2027 period, propose policies aimed at enhancing endogenous resources by promoting development models rooted in local specificities [13,14]. In this context, the Territorial Agenda 2030 formalizes a polycentric vision of European space, recognizing the role of IAs, regions characterized by functional marginality with respect to the decision-making center, at the core of territorial rebalancing strategies [15]. The European Union associates the concept of IAs with the provincial level, defining it in terms of insufficient proximity to major social, political, and economic activities. Specifically, this includes low socio-economic potential and development and limited access to urban centers and the services they provide, as well as restricted accessibility. In Italy, however, the application of the framework occurs at the municipal level, with a focus on spatial marginality [9,16]. This divergence in interpretation reflects differences in the identification of the causes of peripherality, with direct implications for intervention strategies. Policies often tend to oversimplify and categorize the different Italian territorial situations, defining rigid distinctions between inner/peripheral and urban/metropolitan areas in relation to a single center or hub. However, the national settlement structure is more heterogeneous, including both declining industrial areas and areas of spreading urbanization, which does not allow for a binary classification of center and periphery [17].

The Italian context is structured around a polycentric network of small- and medium-sized municipalities coexisting with a few metropolitan areas. Local governments face increasing competition to attract investments, aggravated by cuts in government transfers since the 2000s. In this context, spatial planning has often been used to gain competitive advantage, leading to fragmented and unsustainable urbanization processes. In response, some regional authorities have attempted to overcome these dynamics through legislative reforms aimed at promoting collaborative approaches, though with uneven results [18].

In Italy, the scientific debate and practice in the field of urban and territorial planning have traditionally focused on IM planning models tailored to high-density urban or metropolitan contexts [19,20,21]. This approach has led to the development of strategic planning aimed at managing processes of economic growth, physical transformation, and infrastructure integration in areas characterized by intense sociodemographic dynamics and a high concentration of services. However, this focus has overlooked the need to develop governance models tailored to the low-density conditions typical of IAs. Conventional planning based on metropolitan paradigms fails to exploit the latent potential of territories that function as non-hierarchical settlement networks. In such contexts, settlement dynamics depend on horizontal relationships and ecological and cultural interdependencies more in line with the concepts of bioregions [22] or ecopolitan systems [23].

To comprehend inter-municipal planning in fragmented low-density regions, this study adopts an integrated theoretical framework in which collaborative governance, polycentric networking, and a place-based approach converge to underpin the research perspective. Participatory processes and stakeholder networks facilitate continuous knowledge exchange and foster incremental demonstrable achievements that build mutual trust and secure genuine community involvement. This dynamic holds even where administrative authority is dispersed [24,25]. Simultaneously, networking across functionally defined polycentric territorial contexts enables diverse actors to pool capacities and collective know-how, optimizing resources and expertise [26,27]. Grounded in place-based logic, interventions are tailored to each territory’s unique social, economic, and environmental endowments, promoting integrated asset-driven policies that directly address local vulnerabilities such as spatial inequalities [13,28].

Studies of regional dynamics and multilevel governance show that formal regulations alone cannot ensure effective inter-municipal cooperation; rather, it is the relational capacity of local actors—their ability to build and sustain trust—that proves pivotal [29,30,31]. Such cooperation not only mediates tensions between economic growth and spatial equity [32] but is also shaped by national administrative contexts—legal frameworks, funding mechanisms, and institutional cultures—resulting in varied IM outcomes across Europe [33,34]. Although these strands differ in scale and perspective, they coalesce around inter-institutional cooperation and provide the interpretive lens for examining how municipalities in Italy’s inner areas adopt IM planning instruments, translating governance principles and collaborative ambitions into concrete actions under the SNAI strategy. Applying this perspective to SNAI pilot areas highlights how inter-municipal associations operationalize these high-level principles through specific planning measures and institutional arrangements.

In this view, this paper examines IM planning in IAs, where administrative fragmentation, limited technical and financial resources, and dispersed settlement patterns challenge traditional planning models. Focusing on the 72 pilot areas of Italy’s 2014–2020 SNAI program, it reviews the regional legislative framework for IM planning instruments and the joint management of essential functions—particularly urban planning—by IM associations. Its core objective is to assess whether the inter-municipal scale is recognized as a strategic tier for territorial policy implementation. To this end, this study reconstructs how municipalities in contexts of demographic decline and infrastructural fragility enact IM planning, integrating an analysis of regional regulations with the operational cooperation mechanisms they employ. It highlights both the potential—through synergies between economic development policies and spatial planning practices—and the pitfalls, such as decoupling between economic programming and planning strategies, implementation gaps arising from regulatory heterogeneity, and persistent institutional fragmentation. The methodological framework, thus, addresses a significant knowledge gap in the operationalization of the SNAI paradigm. This study concludes by emphasizing the pressing necessity to align economic policies with spatial planning instruments at the inter-municipal level, thereby ensuring that development strategies promoted by SNAI translate into effective territorial outcomes.

2. The Italian Settlement System Between Polycentrism, Inner Areas, and Inter-Municipal Cooperation

In Italy, patterns of economic and settlement development have historically followed polarized trajectories, shaped by uneven industrialization processes. This has resulted in a complex territorial configuration, where large- and medium-sized urban centers coexist with an extensive network of smaller municipalities, many of which are classified as IAs [35]. Rather than reflecting a binary urban–rural divide, Italy’s territorial structure is characterized by marked heterogeneity: depopulating mountain villages, declining rural areas, and urbanized coastal zones coexist with fragmented yet inherently polycentric territorial framework. Notably, even areas with high tourist flows often lack essential services for local communities. Many of these contexts are undergoing processes of demographic shrinkage, driven by ageing populations and persistently low birth rates, alongside economic stagnation and social disinvestment. These trends undermine the socio-ecological fabric of local communities, weakening their capacity to manage landscape and cultural and environmental heritage, while simultaneously limiting access to basic citizenship rights and hampering the reorganization of local production chains. Significantly, such forms of territorial fragility are no longer confined to traditionally peripheral or rural areas. Increasingly, they affect urban contexts and inter-municipal (IM) systems with historically high levels of industrial concentration. This evolving geography challenges the longstanding dualistic interpretation of territorial disparities as a simple opposition between development and underdevelopment, typically framed in strictly economic terms [36]. Viewed through the lens of polycentric governance, these dynamics reveal the inadequacies of centralized top-down planning approaches that, since the 1950s, have prioritized industrial expansion in selected regions. While such strategies were intended to reduce regional disparities, particularly between the industrialized North and the largely agricultural South, they often had the opposite effect. Public interventions channeled resources into urban growth poles, reinforcing structural imbalances and marginalizing smaller settlements and peripheral areas [37]. Structural reforms and extraordinary interventions in Italy have historically sought to standardize the national development model by directing substantial public resources toward strategic sectors, particularly industry. While these efforts aimed to foster territorial cohesion, they often exacerbated spatial disparities by concentrating on economic growth and demographic expansion in large- and medium-sized urban centers, to the detriment of a wide network of smaller municipalities. Planning processes, heavily influenced by industrial actors and national economic priorities, have, thus, reinforced existing socio-economic imbalances rather than correcting them [38]. Traditional top-down policies further entrenched these disparities by focusing on infrastructure and industrial investment in so-called disadvantaged areas, effectively maintaining a rigid dichotomy between “developed” and “underdeveloped” areas. This persistent spatial polarization has underscored the need for a more integrated approach that aligns economic programming with spatial planning [39]. The constitutional foundation for such an approach can be traced to Article 41 of the 1948 Italian Constitution, which mandates the state to guide public and private economic activity toward socially oriented goals, thereby establishing a normative framework for coordinated intervention.

Attempts to operationalize this integration were evident in instruments such as the National Economic Programs (NEPs) and “Project ’80”, a preparatory document for the Second National Economic Program (1971–75). These initiatives introduced a territorial classification system based on development potential, aiming to coordinate economic and spatial policies within a strategic medium-term planning horizon. Although limited in their practical outcomes, these efforts represented a conceptual shift toward a more holistic model of development planning, recognizing the interdependence of spatial and economic dimensions [40]. Over time, however, the influence of these initiatives waned, particularly in the face of changing political and economic paradigms. Their declining relevance illustrates the limitations of a technocratic planning model that, while innovative in its design, proved insufficient to produce lasting territorial rebalancing [41].

Within this evolving scenario, the concept of “development governance” has emerged as a central analytical and policy concern, emphasizing the need for alignment between urban planning and economic programming objectives. The integration of spatial and socio-economic variables across scales has proven essential for the formulation of effective urban and territorial plans [42].

Although the implementation of socio-economic development programs was often limited, the analytical foundations on which they were based remain noteworthy. These early efforts sought to bridge economic and territorial planning through an integrated framework, aiming to support a more balanced spatial distribution of population and resources at the regional level [43].

From the late 1970s onward, the establishment of regional institutions reinforced the centrality of national planning in identifying socio-economic disparities and defining localized development goals. This period underscored the structural interdependence between economic policy and spatial governance, laying the groundwork for a more integrated and territorially sensitive planning paradigm [44].

A major conceptual and operational shift occurred in the 1990s with the progressive adoption of place-based policies. In contrast to earlier standardized approaches, these new frameworks recognized the heterogeneity of territorial contexts (geographic, demographic, and cultural) and the necessity of tailored interventions. This transformation reflects a broader theoretical reorientation toward governance models that are multi-scalar, adaptive, and attuned to local capacities and dynamics. This period also marked a turning point in Italian policy and institutional architecture, with increased emphasis on public policy effectiveness and the integration of territorial dimensions into broader development strategies. The inclusion of territorial criteria in the allocation and management of European Structural and Investment Funds significantly advanced this shift, enhancing the relevance of local contexts in shaping economic and social interventions. In doing so, it strengthened the coherence between EU cohesion objectives and national efforts to address spatial disparities through context-specific and territorially informed governance mechanisms [45].

A paradigmatic example of Italy’s shift toward place-based policymaking is the National Strategy for Inner Areas (SNAI). Grounded in a polycentric and context-sensitive rationale, SNAI redefines territorial marginality by prioritizing access to essential services—such as mobility, healthcare, and education—over traditional quantitative indicators. It challenges the urban–rural binary by focusing on functional interdependencies between service provision hubs and surrounding peripheral areas, thus aligning with contemporary interpretations of spatial justice and territorial cohesion.

Rather than relying on abstract metrics detached from local realities, SNAI adopts a methodology that evaluates residents’ capacity to exercise full citizenship rights. Central to this approach is the identification of municipal networks—designated as service hubs—around which surrounding municipalities are organized according to degrees of spatial peripherality. This functional reading of territorial disadvantage offers a more nuanced framework for targeting public intervention.

Despite its conceptual innovation, SNAI remains largely embedded within the domain of economic programming, with funding mechanisms primarily aimed at countering demographic decline and supporting local economic revitalization. However, the strategy lacks systematic coordination with spatial and urban planning frameworks. This institutional disjunction limits the operational capacity of place-based approaches and highlights a broader challenge in Italian territorial governance: the persistent fragmentation between economic and spatial planning instruments.

This gap is increasingly significant considering emerging collaborative models—such as negotiated programming and regional strategic plans—that seek to promote a more integrated governance architecture. Yet, the mechanisms for aligning economic investment strategies with spatial planning remain underdeveloped [44]. In this context, the role of local authorities and inter-municipal (IM) associations becomes crucial. These actors not only influence the allocation and management of regional economic resources but also have the potential to drive integrated planning processes at the IM scale. IM cooperation, through the joint exercise of public functions or the creation of new legal entities (e.g., unions of municipalities), offers a strategic pathway to mitigate territorial marginalization and support a more equitable distribution of services [46]. By pooling resources and administrative capacities, such forms of cooperation can generate shared benefits across municipal boundaries and contribute to a more resilient and balanced territorial structure.

The challenges of inter-municipal (IM) planning in Italy exemplify the structural tensions between strategic territorial visions and fragmented local governance. With approximately 8000 municipalities—70 percent of which have fewer than 5000 inhabitants (or 3000 in mountainous areas)—Italy’s territorial system is highly dispersed. While these small municipalities collectively account for only around 17 percent of the national population, they play a critical role in delivering essential public services and maintaining local governance functions. However, their limited administrative capacity often hinders the implementation of complex planning and development strategies.

To address this, national policy has increasingly promoted IM cooperation as a means of consolidating resources, building critical mass, and fostering integrated governance. These collaborative arrangements aim to overcome the inefficiencies of administrative fragmentation by leveraging functional interdependencies among municipalities. In this context, polycentric governance evolves from a descriptive analytical framework to a normative principle that shapes institutional innovation.

Mechanisms such as Unions of Municipalities (UM) and inter-municipal agreements are central to this approach. Originally enabled by Law No. 142/1990 and reinforced by the 2012 “spending review” (Law No. 95/2012), these instruments encourage the joint exercise of strategic functions, including urban and spatial planning, service delivery, and housing policy, particularly in small and peripheral municipalities. While UMs are endowed with legal autonomy and an independent organizational structure, IM agreements offer more flexible contract-based frameworks for cooperation [47].

Both mechanisms contribute to a broader agenda of territorial rebalancing. They support the emergence of distributed development hubs, mitigate the socio-economic effects of demographic decline and ageing in marginal areas, and foster a more equitable spatial distribution of opportunities. Embedded in national policies aimed at reinforcing Italy’s polycentric territorial structure, these initiatives are also consistent with the EU’s cohesion policy, which increasingly links Structural Funds to place-based approaches and multi-level governance. By promoting decentralization, improving connectivity, and generating synergies across local systems, IM cooperation facilitates a diversified and resilient spatial organization. Rather than relying on a single urban core, this model enables a network of functionally specialized centers that integrate economic, social, cultural, and environmental dimensions of development. It also enhances the effectiveness of public service provision and attracts external investment, particularly in underserved regions.

The convergence of polycentric governance, place-based policy, and inter-municipal cooperation offers a strategic framework for rethinking territorial development in Italy. This integrated approach transcends traditional binaries, such as urban versus rural or center versus periphery, by promoting context-sensitive, collaborative, and inclusive governance. It empowers small and peripheral municipalities not only to address structural vulnerabilities, but also to become active agents in shaping sustainable and territorially cohesive futures. Ultimately, the combined implementation of polycentric development principles and IM cooperation transforms the vulnerabilities of inner areas into assets for long-term resilience and spatial equity.

3. Materials and Methods

This study adopts an analytical case study approach to evaluate regional regulatory frameworks and the mechanisms of IM cooperation implemented within the pilot areas identified by the National Strategy for Inner Areas (SNAI) with a specific focus on urban and territorial planning.

The SNAI pilot areas were selected as research case studies because, during their candidacy phase, they demonstrated verified forms of inter-institutional collaboration and the presence of local associative structures. Specifically, candidate areas are required to provide evidence of the joint management of core municipal functions (such as territorial planning, education, health and social care services, mobility, and local development) through institutionalized governance models or topic-specific agreements among municipalities. These characteristics make the pilot areas particularly valuable observation sites for investigating how IM planning is enacted in territories affected by demographic decline and infrastructural weaknesses.

The overarching goal of this research is to understand how, and through which instruments, participating in municipalities translates IM planning into practice in contexts marked by demographic and infrastructural fragility.

The specific objectives have been reformulated into measurable terms:

-

to identify which regional regulatory framework supports IM planning and whether dedicated planning instruments are provided;

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to analyze how local associative structures concretely implement essential IM functions;

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to assess whether IM planning functions are effectively carried out and whether IM planning tools are adopted.

Each level of analysis directly corresponds to these research questions, ensuring consistency between the research aims, methodological design, and analytical outcomes. This research is structured around three complementary and progressively interconnected levels of analysis, as summarized in

Table 1. Methodological framework of this research. Synthesis of the main research phases, including materials, data sources, and outputs.

Research Flow Phases	Materials and Data	Data Sources	Outputs
Analysis of regional legislation	Regional planning laws	Institutional websites of regional governments	Comparison matrix: region; presence of IM instruments (yes/no); types of IM instruments; scope of application; mandatory or optional nature; any specific characteristics
Mapping of associative forms in SNAI pilot areas	Dataset of SNAI pilot area strategies, statutes of municipal associations	SNAI website (www.agenziacoesione.gov.it/, accessed on 23 July 2025), institutional websites of municipal associations	Recognition of associative forms of collaboration declared in the pilot areas’ strategies and, eventually, in the statutes of municipal associations; presence
Analysis of IM planning tools	Dataset of IM urban planning tools in SNAI pilot areas	Institutional websites of municipal associations	Qualitative analysis of a selection of IM urban planning tools

.

• Analysis of regional legislation

The first level of analysis involves a comprehensive review of the national and regional legislative frameworks that regulate inter-municipal cooperation in Italy. Emphasis is placed to the extent to which regional laws provide specific IM urban and spatial planning instruments. A systematic review was carried out of the territorial governance legislation enacted by all 20 Italian regions. Using a structured research protocol, all relevant planning acts (planning laws, decrees, and implementing regulations) were collected into a dedicated database. Each document was examined to determine how it addresses inter-municipal planning, and the provisions were categorized according to the type of instrument (e.g., voluntary agreements versus mandatory mechanisms) and scope of application. The result of this phase is a comparative matrix that highlights the key characteristics and differences between regional legislations and existing gaps. It also offers a detailed overview of how IM planning is institutionally framed throughout the country.

• Mapping of associative forms in SNAI pilot areas

The second phase of this research investigates the governance structures that support inter-municipal cooperation in the 72 pilot areas chosen for the National Strategy for Inner Areas (SNAI). The objective of this study is to map the institutional architecture of local partnerships and to evaluate the extent to which decision-making processes are formalized. Each pilot area was subjected to analysis by the collection and review of candidacy documents, association statutes, and inter-municipal agreements concerning the joint management of essential public services. These documents were used to classify the cooperative structures in place, such as Unions of Municipalities, consortia, and purpose-specific agreements. The focus was placed on the shared management of urban and territorial planning functions, as this is one of the strategic levers for SNAI funding eligibility. The analysis investigates whether such competencies are effectively included among the jointly managed functions, and whether this inclusion has resulted in the activation of inter-municipal (IM) planning tools.

• Analysis of IM planning tools

The third level of analysis focuses on the practical implementation of inter-municipal planning in territories that have formally adopted such instruments. This involves an in-depth review of specific outcomes, such as shared plans, spatial strategies, projects, and other relevant territorial initiatives. The analysis evaluates the structural features and operational mechanisms of these tools to identify successful practices, critical issues, and opportunities for improvement. This step is of significant value in providing insights into the way normative and institutional frameworks translate into real-world planning dynamics and outcomes at a local level.

This three-level methodological framework ensures a coherent analysis that highlights both the normative dimension and the concrete practices of IM planning in a representative selection of Italian IAs.

4. Results

4.1. The Institutional Framework of Inter-Municipal Planning Instruments in Regional Legislation

The analysis of regional urban planning laws (

Table 2. Analytical framework of urban planning legislation by region and inter-municipal planning regulations in the Italian context.

Region	Urban Planning Law (and Subsequent Amendments)	IM Planning Instruments	Regulations
Abruzzo	Regional Law No. 58/2023	Yes	IM plan is an alternative to the municipal plan. UMs with the exercise of urban planning functions develop IM plans for the territory of competence.
Basilicata	Regional Law No. 23/1999	No	-
Calabria	Regional Law No. 19/2002 (updated with Law No. 14/2006)	Yes	Two or more municipalities, including those belonging to different provinces, may proceed with the formation of an IM structural plan with the same contents as a municipal structural plan.
Campania	Regional Law No. 16/2004	No	-
Emilia-Romagna	Regional Law No. 24/2017	Yes	IM plan is an alternative to the municipal plan. Associated municipalities that share urban and territorial planning responsibilities develop and approve IM planning instruments; the same option is available to non-associated municipalities through specific agreements.
Friuli-Venezia Giulia	Regional Law No. 5/2007	Yes	IM applies when at least five municipalities are involved, or at least one-third of those in a province, or a combined population of 30,000; it is carried out across the territories of the participating municipalities through specific agreements entered and approved by the respective municipal councils.
Lazio	Regional Law No. 38/1999	Yes	IM planning is an alternative to the municipal plan. Municipalities falling within the designated territorial areas must collaborate in an associated form for urban and territorial planning; other municipalities may likewise choose to form such associations.
Liguria	Regional Law No. 36/1997	Yes	IM planning is an alternative to the municipal plan and is carried out by associated municipalities or UMs, subject to specific agreements among the municipalities involved.
Lombardia	Regional Law No. 12/2005	Yes	IM planning is an alternative to the municipal plan and is carried out by associated municipalities or UMs, subject to specific agreements among the municipalities involved.
Marche	Regional Law No. 19/2023	Yes	IM planning is an alternative to the municipal plan and is carried out by associated municipalities or UMs, subject to specific agreements among the municipalities involved.
Molise	No regional urban planning law	No	-
Piemonte	Regional Law No. 56/1977	Yes	IM plan is voluntary and an alternative to the municipal plan.
Puglia	Regional Law No. 20/2001	Yes	IM plan is voluntary and an alternative to the municipal plan.
Sardegna	Regional Law No. 45/1989	Yes	IM plan is voluntary and an alternative to the municipal plan.
Sicilia	Regional Law No. 19/2020	Yes	IM plan is voluntary and an alternative to the municipal plan.
Toscana	Regional Law No. 65/2014	Yes	Two or more municipalities, including those belonging to different provinces, may proceed with the formation of an IM structural plan with the same contents as a municipal structural plan.
Trentino Alto-Adige	Provincial Law No. 15/2015 1	Yes	IM planning is expressed in the Community Territorial Plan, which does not replace the municipal urban plan but prevails over it.
Umbria	Regional Law No. 1/2015	Yes	IM plan is an alternative to the municipal plan. The municipality shall prepare the structural plan part, preferably in partnership with neighboring municipalities.
Valle d’Aosta	Regional Law No. 11/1998	No	-
Veneto	Regional Law No. 11/2004	Yes	IM plan is an alternative to the municipal plan. The need for coordination may be established by the municipalities concerned or by the Provincial or Regional Territorial Plan.

¹ Urban planning falls under the authority of the Autonomous Provinces of Trento and Bolzano.

) shows considerable heterogeneity in the design of IM planning instruments. These differences are not only formal, but also substantive, reflecting different orientations towards functional integration and in the structuring of multi-level governance. Only four regions, Valle d’Aosta, Basilicata, Campania, and Molise (the latter without a regional planning law), do not provide for any form of IM planning. In other regions, however, various attempts can be observed to steer IM cooperation towards models of joint planning and territorial coordination; while some only allow voluntary cooperation, others introduce specific instruments aimed at ensuring better coordination of territorial governance strategies between local authorities.

The promotion of IM urban planning reveals different but complementary approaches, particularly in Liguria, Lazio, and Marche. Despite the absence of formal IM planning tools in these regions, legal frameworks have been adopted that are tailored to local needs and promote collaboration in a way that reflects unique governance models. Liguria’s strategy, codified in Regional Law 36/1997, prioritizes flexibility: municipalities are encouraged, but not required, to formulate joint municipal urban plans through voluntary partnerships, often facilitated by existing UMs. This approach is based on the premise that it respects local autonomy while encouraging municipalities to adopt common planning objectives, thus avoiding the use of rigid structures that could limit cooperation.

In contrast, Lazio has adopted a more assertive model. Article 38 of its 1999 Regional Law introduces the General Associated Municipal Urban Plan, which targets municipalities within state-defined “optimal territorial areas”. By linking participation to financial incentives, the region not only streamlines planning within these strategic zones but also encourages neighboring municipalities to voluntarily align themselves with this framework, facilitating the extension of coordinated planning beyond the original boundaries.

Meanwhile, Marche’s innovative 2023 Regional Law takes integration a step further. Its unique General Urban Plan is explicitly linked to the overarching Regional Territorial Plan (RTP), which identifies “integrated territorial systems” at the sub-regional level. The focus here is on binding agreements between neighboring municipalities, transforming fragmented planning efforts into a coordinated and coherent territorial framework. This model directly addresses the issues associated with fragmented governance by establishing strategic cohesion as a prerequisite for sustainable development.

While some Italian regions use IM planning as a complementary tool, others, such as Emilia-Romagna, Piemonte, Veneto, Calabria, Toscana, Puglia, and Sardegna, treat it as a substitute for traditional municipal plans under specific conditions, reflecting a deliberate shift towards integrated territorial governance. In Emilia-Romagna and Piemonte, for example, IM plans serve as coordination tools between local and regional planning levels. Emilia-Romagna’s 2017 legislation (Regional Law 24/2017) empowers clusters of municipalities to draw up General Inter-Municipal Urban Plans in line with broader metropolitan or regional frameworks. Similarly, Piemonte’s Regional Law 56/1977 allows municipalities to bypass General Regulatory Plans in favor of IM urban plans, guided by regional criteria for territorial cohesion. Both regions exemplify an approach in which IM cooperation is institutionally structured rather than left to discretionary initiative.

Veneto and Calabria, meanwhile, are adapting their models to local challenges. In Veneto, the Inter-Municipal Territorial Plan replaces conventional municipal urban plans while allowing for thematic complements that reflect the region’s diverse landscapes and economic priorities. By contrast, Calabria’s Regional Law 19/2002 uses the associated structural plan to unite municipalities facing common vulnerabilities and pool resources to address issues such as depopulation and infrastructure deficits. Toscana and Puglia continue to experiment. Toscana’s Regional Law 65/2014 removes provincial boundaries, allowing municipalities in different provinces to co-create inter-municipal structural plans, which are subsequently supported by operational plans and financial incentives. Similarly, Puglia’s Regional Law 20/2001 takes a flexible approach, requiring municipalities to present joint feasibility studies before drafting IM urban plans, with regional support ensuring full implementation.

Sardegna, through Regional Law 45/1989, treats IM urban plans not as complementary tools to municipal planning, but as functional alternatives characterized by fully overlapping administrative competences. These instruments are essentially equivalent in substance, differing only in their territorial scope and in the fact that their adoption requires formal approval by the municipal councils of all participating municipalities. However, the Sardinian IM plans do not introduce a distinct structural or strategic dimension compared to the municipal plans. Instead, they reflect the framework of the Italian Urban Planning Law of 1942 (Law No. 1150), inheriting its limitations as a rigid compliance-oriented instrument.

Several Italian regions have adopted intermediate planning frameworks that do not replace municipal plans but, instead, foster IM coordination, balancing local autonomy with broader territorial cohesion. In Friuli-Venezia Giulia, Regional Law 5/2007 introduces IM planning through the structural plan, which covers contiguous municipalities. This plan is entrusted to IM associations, unions of municipalities, or other local bodies, and operates in accordance with the Regional Territorial Plan. Lombardia, through Regional Law 12/2005, promotes coordinated planning by encouraging municipalities to develop joint plans. These frameworks support shared territorial, environmental, landscape, and infrastructure policies without replacing the municipal Territorial Governance Plan. In Trentino Alto Adige, Provincial Law 15/2021 introduced the Community Territorial Plan for district communities. This plan establishes IM areas designated for productive, agricultural, and infrastructural functions, while all other urban planning responsibilities remain with municipal plans.

Finally, some regions actively promote IM planning through financial contributions and organizational support. In this context, Toscana, Emilia-Romagna, Friuli-Venezia Giulia, and Puglia stand out for adopting specific measures to facilitate the development and implementation of IM plans, thereby contributing to a more integrated and coherent framework of territorial governance.

4.2. Mapping of Associative Forms Between Municipalities in SNAI Pilot Areas

The territorial distribution of the 72 pilot areas under the National Strategy for Inner Areas (SNAI) reflects a significant macro-regional balance (Figure 1): 55.5% of the areas (40 out of 72) are concentrated in North-Central Italy, with high-density clusters in Emilia-Romagna, Liguria, Lombardia, Piemonte, Veneto, and Lazio. The remaining 44.5% (32 areas) are in Southern Italy, where Abruzzo and Sicilia stand out with five areas each, followed by Calabria, Basilicata, Puglia, Molise, and Campania, with four areas each.

Analysis of the adopted forms of inter-municipal association reveals a complex but patterned framework. Almost all pilot areas, 63 out of 72 (87.5% of the total), are currently linked to at least one IM governance body. This figure shows progress in administrative management processes, in line with the principles of inter-institutional coordination set out in national legislation (Legislative Decree 78/2010 and Law 56/2014), which promote integration between different levels of government for more effective territorial policy management.

Specifically, 48 out of 72 pilot areas (approximately 66.7%) rely on a single associative model, highlighting a consolidated trend towards the centralization of governance and its core functions.

The predominance of “Unions of Municipalities” and “Mountain Communities,” albeit under different names, suggests that most strategies during the 2014–2020 period were managed by a single governing body, benefiting from clearer accountability and procedural efficiency.

Beyond these two main patterns, formal agreements for ad hoc integrated projects and instances of consortia, park authorities, and other IM bodies have been established to protect specific landscapes and cultural assets. This framework shows that more specialized models of collaboration have emerged in areas where specific protection is required. Across the 72 SNAI pilot areas, there are 104 associative governance models, 24 of which integrate several frameworks, covering over 1100 municipalities and underlining the extensive reach of IM cooperation.

UMs predominate in North-Central Italy, particularly in Emilia-Romagna, Toscana and Trentino-Alto Adige. These entities often originated in response to national reforms (Legislative Decree 78/2010 and Law 56/2014) and were subsequently reinforced by regional policies promoting functional aggregation among local authorities.

Mountain communities and their variants are mainly concentrated in the mountainous inner areas of the Apennine and Alpine arcs, Abruzzo, Piemonte, Lombardia, Calabria, and Basilicata. These territories, characterized by complex topography and low population density, rely on the mountain community model to manage services over large, fragmented areas while ensuring that local needs are adequately represented. In these contexts, MCs often represent an institutional legacy adapted to the Italian National Strategy for Inner Areas (SNAI), becoming key implementing bodies of territorial development strategies. Formal agreements and atypical forms of association—such as consortia and joint management bodies involving park authorities and municipalities—are common in areas where local partnerships have pioneered tailor-made solutions, often driven by strict environmental constraints or by objectives to preserve cultural heritage.

Of the 72 SNAI pilot areas analyzed, 24 (33.3% of the total) use several governance frameworks simultaneously, combining UMs, MCs, Regional Parks, and ad hoc agreements. These complex models are unevenly distributed, accounting for 35.0% of areas in North-Central Italy (14 out of 40) and 31.2% in Southern Italy (10 out of 32). This configuration reflects, on the one hand, the need for functional specialization through the activation of sectoral bodies dealing with thematic priorities such as landscape valorization or environmental protection and, on the other hand, the need for political inclusiveness through the involvement of multiple stakeholders in decision-making processes. However, it remains to be seen whether such complexity increases effectiveness in achieving cohesion objectives or, conversely, risks fragmenting governance and making it more difficult to define shared goals.

Of the 72 SNAI pilot areas analyzed, 9 lack any form of IM governance structure, i.e., around 12.5% of these areas are not organized into UMs, MCs, formal agreements, or other collaborative frameworks. Regional disparities are stark: in Southern Italy, almost 1 in 4 areas (23.8%) operate without such structures, reflecting weaker institutional cooperation, while in North-Central Italy, only 9.8% of areas lack IM coordination, underestimating the stronger propensity for cooperation in northern regions.

Abruzzo stands out as having the highest rate of non-cooperation (40% of areas work independently). In North-Central Italy, Lazio has the highest proportion of non-associated areas (66.7%, 2 out of 3), while Emilia-Romagna, Lombardia, and Umbria achieve full participation in collaborative frameworks. Campania is the only southern region where all areas are integrated into governance structures. These data reveal a distinct subset of territories operating in complete autonomy, without formal IM partnerships, raising questions about the effectiveness of cohesion policies in these contexts.

4.3. The Associated Function of Inter-Municipal Planning in SNAI Pilot Areas

The analysis focuses on IM cooperation and the shared management of essential functions, with particular attention to urban and territorial planning. This factor, often overlooked in scholarly debate, is crucial for the selection of SNAI pilot areas, as the current regulatory framework explicitly requires municipalities to associate core functions as a prerequisite for candidacy [48]. This approach recognizes the importance of cooperation among local authorities in the design and implementation of strategies, encouraging municipalities in IAs to reimagine themselves as part of an IM territorial system. For this reason, it is crucial to consider a planning dimension that transcends individual municipal boundaries, enabling the formulation of strategic choices and responses to challenges at a broader territorial scale. The analysis of the functions shared by the municipalities in the pilot areas of the National Strategy for Inner Areas (SNAI) reveals a varied situation at the regional level (

Table 3. SNAI pilot areas: evaluation of inter-municipal associations, shared planning functions, and inter-municipal plan adoption.

Region	SNAI Pilot Area	Local Authorities	IM Planning Function	IM Planning Tools
North-Central Area
Emilia-Romagna	Alta Valmarecchia	UM Valmarecchia	-	-
	Appennino Emiliano	UMM dell’Appennino Reggiano	-	-
	Appennino piacentino-parmense	UM Valli Taro e Ceno; UMM Alta Val d’Arda; UMM Alta Val Nure	-	-
	Basso Ferrarese	UM Terre e Fiumi; UM Delta del Po	●	●
Friuli-Venezia Giulia	Alta Carnia	ITU della Carnia	●	●
	Canal del Ferro—Val Canale	MC del Canal del Ferro e Val Canale
	Dolomiti Friulane	ITU delle Valli e Dolomiti Friulane	●	●
Liguria	Antola Tigullio	UM Alta Val Trebbia; UM le Valli dell’Entella; UM Alta Val d’Aveto; IMA (Torriglia lead municipality)	-	-
	Beigua Sol	UM Stura, Orba e Leira; UM del Beigua	-	-
	Val di Vara	UM della Val di Vara	-	-
	Alta Valle Arroscia	UM dell’Alta Valle Arroscia	-	-
Lombardia	Alta Valtellina	MC Alta Valtellina	●	-
	Alto Lago di Como	MC Valli del Lario e del Ceresio; MC Valsassina, Valvarrone, Val d’Esine e Riviera	-	-
	Appennino Lombardo Alto Oltrepò Pavese	MC dell’Oltrepò pavese	-	-
	Valchiavenna	MC della Valchiavenna	●	●
Piemonte	Val Bormida	MU Alto Monferrato Aleramico; MU Alta Langa; MU Langa Astigiana Val Bormida; MU Suol d’Aleramo;
	Val di Lanzo	MU Valli di Lanzo, Ceronda e Casternone; MU Alpi Graie	●	-
	Valli Grana e Maira	MU Valle Grana; UM Valle Maira	●	-
	Val d’Ossola	MU Valli dell’Ossola	-	-
Trentino Alto-Adige	Tesino	VC della Valsugana e Tesino	●	●
	Val di Sole	VC di Sole	●	●
Valle d’Aosta	Bassa Valle	UM Walser; UdC Mont-Rose; UM Evançon	-	-
	Grand Paradis	UM Grand˗Paradis	-	-
Veneto	Comelico	MU Comelico e Sappada	-	-
	Contratto di Foce Delta del Po	IMA (Rosolina lead municipality)	-	-
	Spettabile Reggenza	MU Spettabile Reggenza dei Sette Comuni	-	-
	Agordino	MU Agordina	-	-
Lazio	Alta Tuscia Antica Città di Castro	MC Alta Tuscia Laziale	●	-
	Monti Reatini	MC del Turano; MC del Salto-Cicolano; MC del Velino; MC del Montepiano Reatino; MC dei Monti Sabini; UM dell’Alta Sabina	-	-
	Monti Simbruini	MC dell’Aniene; MC dei Monti Ernici; RP dei Monti Simbruini; RP dei Monti Lucretili; UM della Valle Ustica; UM del Meda Anienea; UM della Valle del Giovenzano	-	-
	Valle del Comino	XIV MC Valle di Comino; XV MC Valle del Liri; UM Valle di Comino; UM delle Mainarde; UM 5 città; UM Municipi d’Europa	-	-
Marche	Appennino basso pesarese e anconetano	MU del Catria e Nerone	-	-
	Piceno	MU del Tronto e Valfluvione; MU dei Sibillini; UM della Vallata del Tronto	-	-
	Alto Maceratese	MU dei Monti Azzurri; MU Marca di Camerino	-	-
Toscana	Casentino Valtiberina	UMM del Casentino; UMM della Valtiberina Toscana	-	-
	Garfagnana-Lunigiana—Media Valle del Serchio—Appennino Pistoiese	UMM Lunigiana; UM Garfagnana; UM Media Valle del Serchio; UM Appennino Pistoiese	●	●
	Valdarno e Valdisieve, Mugello, Val Bisenzio	UMM del Mugello; UM della Val di Bisenzio; UM Valdarno e Valdisieve	●	●
Umbria	Nord Est Umbria	No inter-municipal association	●	-
	Sud Ovest Orvietano	No inter-municipal association	-	-
	Valnerina	No inter-municipal association	-	-
South Area
Abruzzo	Alto Aterno Gran Sasso Laga	UMM della Laga; CM Gran Sasso; MC della Laga; MC Montagne Aquilane; UM Valle Siciliana	-	-
	Basso Sangro Trigno	UM Maiella Orientale Verde Aventino; MU Comuni del Sangro; UM del Sinello; IMA (Casoli lead municipality); IMA Terre del Sangro; IMA Alto Vastese	●	-
	Gran Sasso-Valle Subequana	No inter-municipal association	-	-
	Valfino Vestina	UM Colline del Medio Vomano	-	-
	Valle del Giovenco—Valle Roveto	No inter-municipal association	-	-
Basilicata	Alto Bradano	UM Alto Bradano	-	-
	Marmo Platano	No inter-municipal association	-	-
	Mercure—Alto Sinni—Val Sarmeto	UM Val Sarmento; UM del Serrapotamo—Alto Sinni; UM del Lagonegrese—Noce Mercure Sinni; UM del Pollino Lucano	-	-
	Montagna materana	IMA (Stigliano lead municipality)	-	-
Calabria	Grecanica	No inter-municipal association	-	-
	Reventino Savuto	UM Monti Ma.Re. da Temesa a Terina	●	-
	Sila e Presila	IMA (Longobucco lead municipality)	●	●
	Versante Ionico Serre	UM del Versante Ionico	●	●
Campania	Alta Irpinia	UM Alta Valle Ofanto; UM Terre dell’Ufita; MC Alta Irpinia; MC Terminio Cervialto	-	-
	Cilento Interno	UM Alto Calore; MC Alburni; MC Gelbison Cervati; MC Calore salernitano	-	-
	Tammaro Titerno	UM Città dei Sanniti; UM Città Telesina; MC del Titerno e Alto Tammaro	-	-
	Vallo di Diano	MC Vallo di Diano	●	-
Molise	Alto Medio Sannio	IMA (Agnone lead municipality)	●	-
	Fortore	UM del Tappino	-	-
	Mainarde	No inter-municipal association	-	-
	Matese	UM delle Sorgenti del Biferno; UM della Valle del Tammaro	-	-
Puglia	Gargano	No inter-municipal association	-	-
	Monti Dauni	UM dei Monti Dauni; UM Casali Dauni; UM dei Monti Dauni Settentrionali; UM Monte Cornacchia	-	-
	Sud Salento	UM di Leuca	-	-
	Alta Murgia	UM ARO 2 Barletta Andria Trani; UM Alta Murgia ARO Bari 4	-	-
Sardegna	Alta Marmilla	UM Alta Marmilla	●	-
	Gennargentu Mandrolisai	MC Gennargentu—Mandrolisai	-	-
Sicilia	Calatino	IMA (Caltagirone lead municipality)	-	-
	Madonie	UM delle Madonie; UdC Val d’Himera settentrionale	-	-
	Nebrodi	IMA (Sant’Agata di Militello lead municipality)	-	-
	Terre sicane	IMA (Bivona lead municipality)	-	-
	Valle del Simeto	UM Corone degli Erei; CM di Catania	-	-

“●” signifies the presence of the analytical element, whereas “-” denotes its absence.

).

In the 72 pilot areas under analysis, only 20 (27.8%) have formally established the associated management of urban and territorial planning among municipalities. Of these, just half (10 pilot areas, 13.9% of the total) have adopted IM urban plans, while the remaining 52 pilot areas (72.2%) lack both formal cooperation agreements and dedicated planning instruments. Notably, those areas that share planning responsibilities but do not possess IM urban plans focus primarily on technical and administrative activities. In such contexts, cooperation manifests in the joint management of authorization procedures for hydrogeological and landscape compatibility across multiple municipalities, the unified provision of cadastral services and support for productive activities, and the coordinated maintenance of road infrastructure and public green spaces.

A macro-region analysis reveals a particularly pronounced territorial divide. Of the 40 pilot areas in the North-Central region, 13 (32.5%) have undertaken associated forms of urban planning, while 8 (20.0%) have implemented IM urban plans. In contrast, of the 32 areas in the South, only 7 (21.9%) engage in associated management of urban and territorial planning, and a mere 2 (6.3%) have adopted IM urban plans. The persistence of this discrepancy indicates that, despite the political interest in territorial cooperation, the operational mechanisms in the field are inadequate to translate collaborative intent into fully shared and formalized urban planning practices.

In some regions, including Liguria, Valle d’Aosta, Veneto, Marche, Puglia, and Sicilia, the function of inter-municipal planning is entirely absent from the adopted territorial strategies. In the remaining pilot areas, this function has been shared, at least formally, in more than 60% of cases in Friuli-Venezia Giulia, Trentino-Alto Adige, Toscana, and Calabria; in about half of the pilot areas in Lombardia, Piemonte, and Sardegna; and in less than one-third of cases in regions such as Molise, Campania, Abruzzo, Umbria, Basilicata, Lazio, and Emilia-Romagna.

Among the experiences analyzed, there are numerous cases of IM planning, but these do not always correspond to the territorial perimeters defined in the 2014–2020 programming cycle of the National Strategy for Inner Areas (SNAI). In fact, several pilot areas are configured as territorial aggregations that include different associations of municipalities or other associative entities, thus requiring the development of territorial strategies capable of facing local governance arrangements characterized by high complexity and institutional fragmentation.

For example, the SNAI pilot area of Basso Ferrarese in Emilia-Romagna covers the territory of two different associations of municipalities: on the one hand, the municipalities association of “Terre e Fiumi” has made progress in drawing up an Inter-Municipal General Urban Plan, while the municipalities association of the “Po Delta” seems to lack a similar urban planning tool. It highlights a critical issue that can arise in spatial planning processes due to different forms of inter-institutional cooperation.

In Trentino-Alto Adige, municipalities in the province of Trento are organized into Valley Communities, which, thus, assume a function of coordination and integration between the policies of each municipality, contributing to the construction of a shared vision of territorial development. These institutions respond to the logic of subsidiarity and inter-municipal cooperation geared toward overcoming administrative fragmentation and enhancing territorial resources from a systemic perspective. These communities have the task of managing supra-local territorial planning through the drafting of a Community Territorial Plan. Also, the two Valley Communities involved in the SNAI pilot areas of “Tesino e Val di Sole” have their own Community Territorial Plans that can support the integration of SNAI strategies, facilitating coherence between local development measures and the strategic guidelines of the province.

The region of Toscana represents an advanced context in the field of IM planning, thanks to a regulatory and institutional path that has encouraged, over time, the emergence of cooperative practices between local authorities. The current regional urban planning system is based on a clear bipartition between the structural plan and the operative plan, which aims to distinguish long-term strategic orientations from local implementation tools. Particularly noteworthy is the growing spread of inter-municipal structural plans, which, in recent years, have involved more than 60% of Tuscan municipalities. This dynamic has been encouraged by the importance of the associations of municipalities, which have played a driving role in promoting joint planning, and by the economic and technical support provided by the Toscana region to strengthen the planning capacity of local authorities. This trend is also particularly strong in the inner areas selected by the National Strategy for Inner Areas (SNAI). In these contexts, there are numerous experiences of IM structural plans and, in some cases, also of IM operative plans, in a logic of progressive convergence towards integrated spatial planning models.

Friuli-Venezia Giulia has introduced a territorial governance model based on Inter-Municipal Territorial Unions (ITUs), which are designed as intermediate bodies with supra-municipal coordination functions. Territorial and urban planning is included among the competences attributed to the ITUs, with a strategic connotation that integrates local policies within a broader and more coherent territorial framework. Through the development of common planning tools, the ITUs have been an attempt to overcome administrative fragmentation and promote the associated management of the basic functions of local authorities.

In Calabria, on the other hand, there is experience of associate planning in the SNAI pilot areas with the drafting of an IM structural plan aimed at integrating and coordinating the spatial policies of the different municipalities involved. These experiences show different approaches to IM planning, reflecting the specific territorial and institutional characteristics of the different Italian regions and highlighting the growing importance of inter-municipal cooperation for sustainable and integrated land management.

5. Discussion

The analysis of regional legislative frameworks reveals a complex and fragmented landscape of IM urban planning in Italy, reflecting tensions between local autonomy and the imperative for functional territorial integration. The analysis highlights how, with a few exceptions, most Italian regions have progressively adapted their urban planning legislation to support IM approaches. Within this evolving framework, two main tendencies can be identified. In certain instances, regional frameworks adopt substitutive logic, whereby higher-tier authorities directly intervene to replace or override local plans, especially in territories affected by marked disparities, environmental risks, or socio-economic vulnerabilities. Therefore, some regional laws still consider municipal and inter-municipal urban plans as alternative rather than complementary instruments with overlapping competences. Both aim to ensure balanced development of settlements, regulate the use of agricultural, tourist, and productive land, and define standards for managing existing building stock and providing social and infrastructural services. From an implementation standpoint, these instruments are essentially equivalent and differ only in territorial extension and the bodies involved in their adoption and approval, which are the municipal councils of participating entities. In other instances, the emphasis is placed on collaborative arrangements that encourage municipalities to voluntarily coordinate their planning efforts through IM agreements or joint institutions, promoting a more horizontal and negotiated form of territorial governance. The substantial heterogeneity observed, ranging from the absence of formal IM instruments in Valle d’Aosta, Basilicata, Campania, and Molise to the sophisticated binding models of Marche or the substitutive approaches of Emilia-Romagna and Sardegna underscores the lack of a coherent national paradigm, leaving regions to develop responses heavily influenced by local political cultures, historical contexts, and perceived territorial challenges. This legislative patchwork demonstrates different conceptualizations of multi-level governance: while some regions (e.g., Liguria) prioritize voluntary cooperation anchored in flexibility and respect for municipal sovereignty, others (e.g., Lazio, Marche, Emilia-Romagna, Piemonte) adopt more assertive models, employing strategic spatial designations (“optimal territorial areas”, “integrated territorial systems”), binding agreements, financial incentives, or even the substitution of municipal plans to steer collaboration towards broader territorial cohesion goals. However, approaches treating IM plans merely as administrative alternatives without a distinct strategic dimension (as in Sardegna) risk perpetuating the limitations of traditional municipal planning on a larger scale. The high incidence of financial incentives and organizational support, as observed in Toscana, Emilia-Romagna, Friuli-Venezia Giulia, and Puglia, underscores the recognition that enabling legislation alone is inadequate for effective IM planning. The implementation of effective IM planning is contingent upon dedicated resources and capacity building. The framework that emerged from the analysis suggests a strong heterogeneity in the IM governance models adopted in the SNAI pilot areas. This is indicative of both institutional consolidation logic and adaptive responses to territorial and cultural constraints and specificities. The preponderance of Unions of Municipalities and Mountain Communities in inner areas is indicative of a progressive trend towards the functional integration of local administrations in the constitution of specific bodies. While this approach aligns with the SNAI framework and holds potential for enhanced coordination beyond basic inter-municipal agreements (particularly in managing essential services), its implementation reveals significant challenges. In approximately one-third of pilot areas, hybrid configurations and ad hoc agreements have emerged, highlighting two key issues: first, the practical difficulties of consolidating numerous municipalities into a single entity; second, the necessity for tailored governance models that actively engage sectoral stakeholders in specialized domains like landscape valorization and environmental protection. While acknowledging the potential benefits of enhanced policy adherence to local needs, this increased institutional complexity gives rise to significant concerns regarding the maintenance of clarity in common objectives and the actual effectiveness of cohesion strategies. Previous studies have highlighted how the increased number of bodies and agreements may, in certain instances, result in the generation of overlaps and delays in decision-making processes, particularly within contexts characterized by constrained administrative budgets [49]. Regional disparities in the presence or absence of IM collaboration structures, which are particularly marked in the southern area, draw attention to the institutional and organizational barriers that may limit the implementation of cohesion policies. This dynamic may adversely affect local development outcomes and the management of shared functions, as well as the way incentives and funding are managed in territorial planning, undermining the overall strategic coherence and leading to the risk that the lack of governance coordination results in further fragmentation.

The results highlight the marginal role and pronounced heterogeneity of IM planning mechanisms in the pilot areas. The low proportion of areas that formally share the management of urban and territorial planning and, even more notably, those equipped with fully developed IM instruments reveals a significant implementation gap between the cooperative ambition promoted by SNAI and actual practices. This gap is not only quantitative, but also has a strong geographic dimension, since the marked North-Central versus South imbalance reflects structural inequalities in institutional capacity and in the maturity of cooperation processes among Italian regions. Such inequalities risk exacerbating rather than reducing the territorial disparities that SNAI aims to address. The analysis further uncovers a functional ambivalence in the shared management of IM planning. In those contexts where collaboration exists, it tends to focus mainly on technical and administrative tasks, such as permitting procedures, cadastral services, and maintenance, while the development of a common strategic vision remains neglected. Although this approach meets formal requirements, it undermines the innovative potential of SNAI, which was originally conceived to foster a systemic reorganization of development in inner areas. Institutional fragmentation appears as an additional critical issue because SNAI boundaries often do not coincide with those of existing associations, or because some regional strategies lack any planning function at all. These misalignments generate operational complexities and risk incoherence, which, in turn, call for governance models that are adaptive and capable of operating across multiple territorial scales. Nonetheless, certain virtuous experiences demonstrate that effective integration can be achieved when an enabling regional regulatory framework is in place, when dedicated technical and financial resources are provided, and when intermediate governance structures are robust and legitimate. These initiatives often build on earlier processes and suggest that SNAI can catalyze significant IM planning efforts in contexts already endowed with institutional maturity, whereas initiating such processes ex novo in more fragile areas remains challenging.

The Italian legislative framework regulating municipal urban planning is notably complex and heterogeneous and is the result of long historical and institutional evolution marked by the gradual devolution of powers from the central state to the regions [50]. The concept of the Inter-Municipal General Urban Plan was first introduced by the National Planning Law No. 1150 of 1942. Rooted in a hierarchical and rational comprehensive planning paradigm, the law extended the principles and objectives of the General Urban Plan to a broader IM scale, promoting a coordinated spatial vision among multiple local authorities. Since then, this framework has significantly evolved, particularly following the 2001 constitutional reform of Title V, which decentralized planning authority further. This has led to a fragmented mosaic of regional legislation that variably emphasizes either municipal autonomy or integrated governance. Over time, IM planning has gained increasing relevance as a response to fragmented local governance and as a tool for promoting coherent and coordinated spatial strategies. Originally associated with the joint management of local services, IM cooperation has expanded into urban and spatial planning, structured through both formalized and informal arrangements. These rely on voluntary participation and institutional agreements that establish shared responsibility for long-term territorial governance.

Within this broader framework, IM cooperation has generally followed three main trajectories: local development policies (such as territorial pacts and strategic plans), shared service management (through unions, associations, and inter-municipal agreements), and spatial planning in a strict sense. The scholarly literature often distinguishes two main models of IM cooperation: a cooperative model, which involves formalized joint functions and may lead to new legal and institutional entities, and a collaborative model, which is more flexible and informal, that is typically limited in duration and scope [51]. Despite these frameworks, IM planning continues to face significant political, institutional, and operational challenges. Long-standing traditions of municipal autonomy, combined with structural asymmetries and the lack of adequate regulatory and financial incentives, often hinder effective collaboration. Many municipalities are reluctant to relinquish control over land use decisions, particularly in strategic sectors like economic development. Moreover, disparities in administrative capacity, financial resources, and territorial characteristics complicate the creation of a shared spatial vision. National and regional policies have yet to adequately support or reward successful IM practices, thereby reinforcing institutional fragmentation. IM planning is inherently shaped by complex decision-making processes, often emerging from conflict or competition among municipalities. Increasingly, these processes are structured around participatory mechanisms involving institutional actors and local communities alike, with the goal of co-producing territorial strategies and aligning planning efforts within an integrated governance framework. The term “inter-municipality” refers to a formalized form of cooperation among municipalities supported by legal and administrative structures to facilitate ordinary territorial governance. Recent initiatives reflect a paradigm shift: rather than viewing inter-municipal cooperation as a strategy exclusive to metropolitan areas, it is increasingly recognized as a standard tool for territorial governance across all settings. Within this reconceptualization, IM planning is seen to reorganize fragmented governance, redistribute responsibilities and resources more equitably, and empower even the smallest municipalities [52]. This allows for pooling of technical and financial resources, streamlining planning processes, and strengthening political influence. It also fosters enduring alliances based on solidarity and shared objectives, including environmental sustainability, rural development, and social innovation.

Nonetheless, several barriers persist. The deep-rooted tradition of municipal sovereignty continues to fuel resistance to shared planning, especially where strategic competencies are concerned. These ideological tensions are compounded by internal disparities (financial, administrative, and political), which can transform cooperation into a source of friction rather than synergy. The lack of adequate incentives further weakens efforts to institutionalize IM planning. National and regional policies rarely provide additional funding or competitive advantages to effective IM initiatives, which undermines the formation of stable territorial networks. Territorial and social disparities within the same inter-municipal area, such as differences in geography, infrastructure, or demographics, also make it difficult to develop cohesive spatial strategies.

To overcome these limitations, IM planning must be reimagined as a strategic tool capable of addressing complex challenges like sustainable mobility, the circular economy, and territorial digitalization. Inspired by the strategic metropolitan planning approach of Law No. 56/2014, IM planning should prioritize systemic objectives over procedural formalities. This shift would enhance its strategic focus and operational effectiveness. Concurrently, targeted incentive mechanisms, such as dedicated regional funds, recognition in EU funding rankings, and streamlined authorization processes, are essential. These measures should be supported by a revised regulatory framework that guarantees IM associations financial autonomy and access to skilled personnel for managing joint projects.

Strengthening democratic legitimacy is equally important. This can be achieved through inclusive processes such as public consultations, thematic working groups, and place-based planning practices, ensuring that strategies reflect local needs and counteract perceptions of externally imposed plans. Furthermore, thematic networks among municipalities with shared interests (e.g., green economy, rural tourism, or social services) can foster cooperation based not only on geographic proximity, but also on common development goals. Spatial governance encompasses the decisions and actions shaping territorial organization from urban planning to public investment at all levels of government. It aims to guide spatial transformation toward equitable and sustainable outcomes by integrating public policies with private initiatives [53]. While voluntary municipal associations already collaborate in service management, often motivated by funding opportunities, skepticism toward inter-municipal planning persists, especially in demographically declining areas. This reluctance stems from limited political will and structural disadvantages in these inner peripheries [48,54,55]. Nevertheless, IM plans can initiate a virtuous cycle of cooperation in such territories. Through shared regulatory frameworks and context-specific planning approaches, municipalities can better address service gaps, inaccessibility, and adverse socio-economic and demographic trends. Accordingly, IM planning should be reconceived as a strategic, flexible, and non-prescriptive instrument, akin to metropolitan strategic plans. Positioned at an intermediate level of governance, it can play a vital role in coordinating territorial policies and enhancing coherence across spatial governance tools, particularly given the diminishing role of provinces.

6. Conclusions

This study has explored the potential and limitations of IM planning within Italy’s inner areas, focusing on the institutional and spatial configurations that emerged from the implementation of the National Strategy for Inner Areas (SNAI). By examining a range of legislative, policy, and planning frameworks, as well as IM association practices, this analysis has demonstrated that the IM scale is not merely a functional necessity, but also a strategic tier of governance, particularly in territories marked by demographic fragility, infrastructural deficits, and administrative fragmentation. The findings highlight the role of inter-municipal cooperation as an enabling condition for the coordination of essential territorial functions, with spatial planning at the core. However, persistent structural, institutional, and cultural constraints continue to hinder the full institutionalization and effectiveness of collaborative governance models. Among these constraints are asymmetries in administrative capacity, the persistence of strong traditions of municipal autonomy, and the absence of consistent regulatory and financial incentives. These findings are consistent with broader theoretical reflections on spatial governance and regional development found in the literature. The conceptual evolution of IAs, from being viewed as geographically peripheral spaces to being interpreted through relational, functional, and institutional lenses, necessitates governance models that transcend the traditional urban–rural dichotomy. The shift from hierarchical, sectoral, and top-down planning to more flexible, place-based, and polycentric approaches has created new opportunities for addressing territorial inequalities. However, the practical implementation of these paradigms remains uneven and is often fragmented. As emphasized in academic and policy literature, the effectiveness of IM planning depends heavily on the capacity of local actors to mobilize resources, foster trust, and construct durable institutional arrangements. While polycentric governance is increasingly valued in national and EU policy discourse, empirical evidence from Italian regions suggests a significant gap between normative principles and operational realities. The lack of systematic integration between spatial planning and socio-economic programming, regulatory heterogeneity across regional contexts, and fragmented administrative cultures all continue to undermine the transformative capacity of IM planning.

The SNAI case study exemplifies both the opportunities and the limits of current planning paradigms. Although the strategy innovatively redefines marginality in terms of access to essential services and functional interdependencies, it remains largely confined to economic programming and is only partially integrated into spatial planning practices. This misalignment undermines the holistic development vision that underpins the place-based paradigm, weakening the operational effectiveness of policy interventions. Moving forward, the challenge lies in consolidating IM cooperation as a durable institutional infrastructure capable of sustaining integrated planning practices. This requires not only legal and financial incentives, but also a cultural shift in territorial development governance, one that embraces the complexity of IAs as a source of innovation, resilience, and spatial justice. In this sense, the IM scale should be reimagined not simply as a pragmatic response to administrative fragmentation, but as a strategic arena for reconfiguring territorial relations and achieving more equitable and sustainable development.

In conclusion, IM planning holds significant potential as a mechanism for more inclusive and balanced territorial development. Its success depends on a strategic vision, robust regulatory backing, and adequate financial incentives. Reinforcing governance at the intermediate level can help prevent the marginalization of small municipalities while unlocking local resources and capacities. Italy’s experience offers valuable insights for other European countries facing similar governance challenges in inner peripheries, areas often neglected by conventional planning approaches. Despite institutional complexity and uneven results, Italy’s longstanding experimentation with IM cooperation demonstrates the feasibility and necessity of integrated territorial governance in fragmented contexts. However, an underlying and widespread mistrust in the efficacy of planning instruments, which are often perceived as overly technocratic, disconnected from local needs, or slow to produce tangible results, continues to erode stakeholder engagement and hampers the long-term institutionalization of integrated planning practices. Flexible, voluntary, and place-based approaches supported by enabling legislation and targeted incentives can empower even structurally disadvantaged municipalities to act collectively, build capacity, and develop shared spatial visions. Reframing IM planning as a mainstream governance model, rather than a metropolitan exception, underscores the importance of adapting institutional innovation to local realities. This lesson is especially relevant for European contexts marked by demographic decline, infrastructural deficits, and administrative dispersion. Ultimately, EU and national policies should recognize and invest in intermediate governance structures as critical drivers of territorial cohesion, enabling inner peripheries to shift from marginalization to active participation in shaping their spatial futures.