Moorpark is a city in Ventura County in Southern California. Moorpark was founded in 1900. The town grew from just over 4,000 citizens in 1980 to over 25,000 by 1990. As of 2006, Moorpark was one of the fastest-growing cities in Ventura County. The population was 34,421 at the 2010 census, up from 31,415 at the 2000 census.