Los Angeles County

County in southwestern California, on the Pacific Ocean; area 10,541 sq km/4,070 sq mi; population (1990) 8,863,200. One of the most urban US counties, it centres on the city of Los Angeles, the capital, and is the most populous county in the nation. For the first half of the 20th century it was the richest US agricultural county; its oilfields, opened from 1891 through to the 1920s, also contributed to economic growth. Major cities include Long Beach, Pasadena, Santa Monica, Burbank, Glendale, and Beverley Hills.

The Angeles National Forest, in the San Gabriel Mountains, occupies much of the north of the county, along with the southern Antelope Valley. Below the mountains sprawls the city of Los Angeles, from the suburban San Fernando Valley across the Santa Monica Mountains, through the Los Angeles Basin and down the coast along the South Bay. Santa Catalina and San Clemente islands are also part of the county.