This study reports on changing settlement patterns in the lower Tiwanaku Valley during the Formative (1500 B. C.-A. D. 100), Classic (A. D. 400-800), and Postclassic (A. D. 800-1100) periods. Based on the association of agricultural features with these site distributions, as well as the consideration of ethnohistoric and ethnographic information, it is argued that fundamental principles of the political and economic organization of the Aymara ayllus and markas can be inferred from the archaeological evidence. It also is suggested that Tiwanaku articulated local elites through mechanisms of reciprocity and common ideological denominators rather than through direct intervention and control of local sociopolitical hierarchies.