The Arizona Water Use Program relies heavily on recent aerial photography and satellite images to both detect and delineate active farm parcels in Arizona. The boundaries of the active farm parcels are traced using Geographic Information Systems software to estimate irrigated acreage. These parcels are then visited by Arizona Water Science Center staff. Data collected remotely and data collected in the field are used to estimate acreage, crop type, and total irrigation withdrawals. The Arizona Water Science Center, Tucson, Arizona, conducts this work for both the national 5-Year water use compilation and a cooperative annual program with the State of Arizona.