The lower Santa Cruz area includes about 5,400 square miles in south-central Arizona and is the second largest agricultural area in the State. The area depends mainly on ground water for irrigation, and in 1976 about 966,000 acre-feet of ground water was pumped from the area. As a result of the large-scale long-term withdrawal of ground water, water levels have declined , and the direction of ground-water flow has changed. Since 1923 , declines of nearly 500 feet have occurred near Stanfield. Information shown on the maps (scale 1:125,000) includes depth to water, altitude of the water level, specific conductance, fluoride concentration, change in water level (1923-77), and land use. Hydrographs of the water level in selected wells and a table of historical pumpage also are included.