Field survey in the territory of ancient Etruria has revealed a dense pattern of rural settlement in the period that the cities of Etruria began to flourish. The precise nature of this rural settlement is only gradually emerging. The primary research presented in this study is an analysis and interpretation of the evidence collected in the Albegna Valley/Ager Cosanus Field Survey. It provides an introduction to the landscape of the survey area and an account of previous archaeological fieldwork, and it goes on to present and discuss the settlements and the settlement patterns recovered by the survey. It also examines the Etruscan burials both from the survey work and from previous excavations and evidence for farming and subsistence recovered from the countryside, and provides a catalogue of ceramic finds. From the evidence of the survey, the author reconstructs a population history and economic history of the area.