Household archaeology conducted at the site of Xaltocan, an important regional center in the northern Basin of Mexico, illustrates how the everyday actions of ordinary people contribute to the rise and decline of ancient polities. Through a study of long-term change and variation from multiple household contexts, this article reconstructs how the economic and political activities of ordinary households were central to the construction and reproduction of political institutions, social structures, and regional systems of exchange from the period of Xaltocan's founding around A.D. 900 through its conquest in A.D. 1395. Along with the other contributors to this volume we emphasize that households are not simply influenced by broader processes of change and development in a trickle-down fashion, but rather that micro-and macro-structures are mutually constituted, with household decisions and actions having both intended and unintended consequences at the macroscale.