Hiding in plain sight: rethinking the size and complexity of Iron Age hillforts in NW Iberia thanks to aerial archaeology and geophysics

This paper tackles one key limitation in the analysis of Iron Age communities in the Northwestern Iberian Peninsula: the limited exploration of areas beyond the fortified settlements known as castros (hillforts). The vast majority of archaeological studies have focused exclusively on the areas inside the walls of these settlements, which are highly prevalent and prominent within the region. At the same time, knowledge about external spaces remains minimal. We seek to employ a combination of remote sensing techniques, such as LiDAR, aerial imagery and geophysical survey, to provide insights into the broader landscapes of the Iron Age. While remote sensing has a longstanding global tradition, its application in this area has been constrained by historical challenges, such as the limited availability of imagery and the complex characteristics of the regional landscape. Recent technological advancements, including improved access to geospatial data and the expansion of LiDAR capabilities, have significantly enhanced the potential for archaeological discoveries. The landscape's composition poses further challenges for remote sensing approaches, with much of the region dominated by forests and scrubland, and a highly fragmented pattern of small fields, which implies a low visibility of the soil surface and difficulties for surveying continuously over large areas. Despite these obstacles, the paper demonstrates the potential of remote sensing techniques to transform our understanding of Iron Age landscapes within the region, moving beyond the traditional focus on castros and broadening the archaeological perspective.

Iron Age hillforts. NW Iberian Peninsula. Aerial archaeology. Geophysics. UAV.