The Cuyama Valley Groundwater Basin, DWR Bulletin 118 Basin No. 3-13, is situated between the Caliente Range to the north and the Sierra Madre Mountains to the southwest. The valley trends east and is drained by the Cuyama River which is the primary source of recharge to the groundwater basin. The basin overlies an area of approximately 147,200 acres (230 square miles) which extends into four counties, including San Luis Obispo County, Santa Barbara County, Kern County, and Ventura County. The basin area in San Luis Obispo County is approximately 32,600 acres (51 square miles).