The South Mountain Oil Field is a large and productive oil field in Ventura County, California, in the United States, in and adjacent to the city of Santa Paula. Discovered in 1916, and having a cumulative production of over 158 million barrels (25,100,000 m³) of oil, it is the 37th largest oil field in California and the second largest in Ventura County (after the Ventura field). As of the beginning of 2009, it retains 316 active wells, and has an estimated 1.4 million barrels (220,000 m³) of oil remaining recoverable with current technology.