Los Angeles , city, seat of Los Angeles county, southern California, U.S. It is the second most populous city and metropolitan area (after New York City) in the United States. The city sprawls across a broad coastal plain situated between mountains and the Pacific Ocean; the much larger Los Angeles county, which encompasses the city, contains some 90 other incorporated cities, including Beverly Hills, Pasadena, and Long Beach. The county also encompasses two of the Channel Islands, Santa Catalina and San Clemente; Mount San Antonio, familiarly known as Mount Baldy or Old Baldy, 10,046 feet (3,062 metres) high; more than 900 square miles (2,330 square km) of desert; and 75 miles (120 km) of seacoast.Since the city and the county are interwoven geographically, culturally, and economically, any consideration of Los Angeles must, to some degree, involve both entities. Population density around the metropolitan area varies greatly—as low as one person per square mile in mountainous areas and as high as 50,000 per square mile near downtown Los Angeles.