AbstractDuring the Early Agricultural period (2100 BC–AD 50), preceramic farmers in the Sonoran Desert invested considerable labor in canal-irrigated field systems while remaining very residentially mobile. The degree to which they exercised formal systems of land tenure, or organized their communities above the household level, remains contested. This article discusses the spatial and social organization of Early Cienega–phase settlements in the Los Pozos site group, an Early Agricultural site complex located along the Santa Cruz River in southern Arizona. At Los Pozos, the formal spatial organization of seasonal farmsteads suggests that despite continued residential mobility, multihousehold lineages maintained distinct territories. Enduring “house groups”—likely lineal groups—are associated with disproportionately large cemeteries, suggesting the revisitation of ancestral territory through occupational hiatuses. However, variability in the formality and permanence of Early Cienega–phase settlements throughout the region indicates a flexible continuum of occupational mobility. These higher-order affiliations were only expressed in persistent settlements near highly productive farmland, where the relative priority of households over improved land might be contested.