Thanks to the analysis of archaeological data relating to the agricultural and pastoral practices of a territory, it is possible to obtain numerous information, both of an ecological nature, and about the populations who lived there. With the reconstruction of the agro-pastoral dimension of a community it is however possible to understand not only the aspects linked to the exploitation of a territory, the subsistence and demography of a given group, but also more generally the social organization itself. Through this particular approach, which we could define as “agro-economistic”, it is therefore possible to investigate in a more articulated way the ancient communities, the relationships between them and the historical phenomena that occurred to them. Through a model developed in a GIS environment and with the application of Land Evaluation techniques it is possible to reconstruct and simulate the agro-pastoral exploitation of a territory (here the Ager Tarquiniorum at the end of the first millennium BC), calculating the food production of each settlement, as well as the consequent demography maximum sustainable. At the same time, through these data, it is possible to verify - on a quantitative basis - the socio-political models proposed by scholars for the communities or to propose new ones. Thanks to the 170 identification of sites specialized in particular productions, villages capable of producing a surplus, or vice versa non-self-sufficient settlements, it will be possible to articulate in detail these socio-political models, hypothesizing exchange networks, hierarchical relationships, or competitive relationships between the different sites. Through this approach, it is also possible to describe the historical events that occurred also from a demographic point of view, with a rough reconstruction of the population involved, further enriching the reconstructions proposed. The scenario obtained will also be compared with similar studies applied to the territory of the Monti della Tolfa and Valle del Fiora. Doing so, the different choices made by the community, will further enrich the picture hypothesized up to now about the passage from the villages... to the cities, in Southern Etruria.