This study presents an integrated geophysical–geomatic approach for the investigation of archaeological sites, combining low-frequency Ground-Penetrating Radar (GPR) and close-range photogrammetry at the Archaeological Park of Abellinum (southern Italy). Unlike conventional applications using high-frequency antennas, the low-frequency GPR system employed in this study enabled deep subsurface imaging, allowing reconstruction of buried stratigraphic and architectural features to depths of several metres. This enhanced penetration capacity facilitated a more comprehensive understanding of the investigated environments, by complementing rather than replacing high-frequency surveys and expanding the interpretable volume in complex urban and peri-urban contexts. GPR reflection data were integrated with high-resolution photogrammetric surface models, enabling direct comparison between visible structures and subsurface geometries. The combined dataset provided precise correlations between surface features and subsurface anomalies, demonstrating the potential of this integrated methodology for detailed archaeological interpretation. Overall, this approach offers a scalable, non-invasive framework applicable to other complex archaeological landscapes, supporting both research objectives and long-term heritage management. By systematically combining low-frequency GPR with high-resolution photogrammetry, the study introduces a methodological contribution that extends interpretative depth well beyond the limits of conventional surveys.