Surveys and excavations along the Gila River, Arizona, between Florence and Casa Grande provide sufficient information on habitation-site and agricultural-feature location to permit preliminary assessment of land use and settlement patterning during the Hohokam Classic period (A.C. 1150--1400). A diverse subsistence base supported the inhabitants of this area. Irrigation agriculture, dry farming, and floodwater farming were all practiced by occupants of habitation sites located in a zone parallel to the river. Locations of fields reveal decreasing intensity of land use with increasing distance from the river. Spacing of sites with platform mounds suggests that the population within and around each of these sites constituted a unit of significance in control of water resources. Evidence for centralization of authority in riverwide water management is currently lacking.