The San Ardo Oil Field is a large oil field in Monterey County, California, in the United States. It is in the upper Salinas Valley, about five miles (8 km) south of the small town of San Ardo, and about twenty miles (32 km) north of Paso Robles. With an estimated ultimate recovery of 532,496,000oilbbl of oil, it is the 8th-largest producing oil field in California, and of the top twenty California oil fields in size, it is the most recent to be discovered (1947). As of the end of 2006, the principal operators of the field were Chevron Corp. and Aera Energy LLC.SettingA familiar sight to travelers on U.S. Highway 101 between Los Angeles and San Francisco, the oil field is located about midway between Paso Robles and King City, in the southern part of Monterey County, at the Alvarado Road exit from U.S. 101. Most of the field is on the east bank of the Salinas River and in the adjacent hills of the Coast Ranges. Overall it is about five miles (8 km) long by two wide, and its productive area encompasses 4390acre. Elevations on the oil field range from approximately 430ft at the Salinas River to around 1100ft in the hills to the east; the densest area of operations is on the flat land in the river valley.Vegetation in the oil field area varies from riparian in the immediate vicinity of the Salinas River, to grassland, chaparral, and oak woodland in the hills and uplands, although much of the vegetation has been removed in the central area of active operations. Land immediately north of the oil field in the Salinas River Valley is agricultural, while other adjacent land, which is mostly hilly, is predominantly used for livestock grazing.