Oak Park is an unincorporated community in Ventura County, California, United States. When developed in the Simi Hills in the late 1960s, a single road provided the only access to the community from Agoura Hills, California, in neighboring Los Angeles County. As of the 2010 census, Oak Park had a population of 14,266, down from 14,625 at the 2000 census. For statistical purposes, the United States Census Bureau has defined Oak Park as a census-designated place (CDP). The census definition of the area may not precisely correspond to local understanding of the area with the same name.
Oak Park is the biggest unincorporated community in Ventura County. Residents of the community have through votes declined to set up an independent city, and also declined to be annexed into neighboring Thousand Oaks.
Oak Park has had human occupation from about 5500 B.C. to the present day. It lies within a zone including the early Millingstone Horizon and inland Chumash Indians. Indians camped throughout the area as they collected acorns, yucca, and other food. The sites in the area include major villages, smaller camps and several rock shelters.