Los Angeles is a city in Southern California.
Los Angeles County, California . The county is home to more than one-quarter of California residents and is one of the most ethnically diverse counties in the U.S. Its county seat , the City of Los Angeles , is also its most populous city at about four million . Southern California . The region is traditionally described as eight counties , based on demographics and economic ties : Imperial , Los Angeles , Orange , Riverside , San Bernardino , San Diego , Santa Barbara , and Ventura .