The growth of the city of Rome was dependent on its ability to exploit the resources of its hinterland. Although this eventually extended to incorporate the entire Mediterranean seaboard, the resources of the Tiber valley continued to nourish the city. This study examines how the Valley functioned in terms of its economic and social geography, via the organisation and dynamics of the brick industry. Through an archaeometric approach to the fabrics of stamped bricks, coupled with social networks analysis, the study arrives at an understanding of the social and economic relationships which characterised the city-hinterland relationship. Patterns of land exploitation are studied by locating clay sources for bricks carrying the stamps of various figlinae and praedia, suggesting particular methods of land-tenure and sources of social power. The dynamics of how these change over time point to the conscious manipulation of social and physical networks in the industry.