This paper presents a study of Iron Age (IA) societies through the analysis of architecture and built space. The approach is focused on a small area in the northwest of the Iberian Peninsula, and constructs a small-scale narrative that seeks to identify different social dynamics concerning the onset, development and decline of the fortified habitat (between the ninth and first centuries BC). Three main spheres of human habitation are assessed: the environment of the household, the construction of collective and non-domestic buildings and the development of settlement planning. The main characteristics of these spheres are discussed and summarised, and they are understood as part of the same dynamic that reflects how the IA communities of northwest Iberia were structured. The main objective of the paper is to employ this methodology to study social dynamics at different scales and thus build a multi-scale historical and archaeological narrative about the development of heterogeneous processes in IA societies.