Classification System and Characteristic Analysis of Cultural Route Landscapes in the Nanling Corridor: An Empirical Study on the Hunan–Guangdong Ancient Road

Cultural routes, an important concept in heritage conservation, represent an innovative paradigm that is reshaping the contemporary trajectory of cultural heritage research. The Nanling Corridor satisfies the four core criteria for cultural routes—temporal continuity, spatial distribution, cross-cultural attributes, and specific historical functional roles—and stands as a paradigmatic indigenous cultural route in China. Focusing on the Hunan–Guangdong Ancient Road—a core segment of the Nanling Corridor—this study integrates historical document analysis, representative sample field surveys, and a historical restoration method to systematically classify and characterize the ancient road’s landscape features. The study findings indicate that the Hunan–Guangdong border region within the Nanling area is endowed with a distinctive natural geographical setting and a complex socio-cultural context. Against this background, landscape elements are categorized into two primary clusters: those directly associated with the ancient road and those indirectly linked to it. The directly associated landscapes are further subdivided into four categories: the cross-territorial route, meso-scale hubs enabling land–water transfer, widely distributed micro-scale ancillary facilities, and intangible engineering techniques. The indirectly associated landscapes encompass four dimensions—military defense, population migration, commercial trade, and religious practice—each demonstrating unique landscape attributes while sharing homologous formative mechanisms. This study aims to provide a China-focused research reference for the international theory of cultural routes through the systematic study of the landscapes along the Hunan–Guangdong Ancient Road within the Nanling Corridor.