Thousand Oaks is the second-largest city in Ventura County, California, located in the northwestern part of Greater Los Angeles. Approximately 15 miles (24 km) from the city of Los Angeles and 40 miles (64 km) from Downtown Los Angeles, it is named after the many oak trees present in the area. The city forms the central populated core of the Conejo Valley. Thousand Oaks was incorporated in 1964 and has since expanded to the west and east. Two-thirds of the master-planned community surrounding Westlake and most of Newbury Park were annexed by the city during the late 1960s and 1970s. The Los Angeles County–Ventura County line forms the city's eastern border with the city of Westlake Village. The population was 126,966 at the 2020 census, up from 126,683 at the 2010 census.