The Los Angeles metropolitan area, also known as Metropolitan Los Angeles or the Southland, is the 13th largest metropolitan area in the world and the second-largest metropolitan area in the United States.
The metropolitan area is defined by the Office of Management and Budget as the Los Angeles-Long Beach-Santa Ana metropolitan statistical area containing consists of Los Angeles and Orange counties, a metropolitan statistical area used for statistical purposes by the United States Census Bureau and other agencies.
Los Angeles and Orange counties are the two most populous counties in California, and Los Angeles, with 9,819,000 people in 2010, is the most populous county in the United States. The combined Los Angeles metropolitan area is home to 15.4 million people, making it the most populous metropolitan area in the western United States and the largest in area in the United States. The metro area has at its core the most densely populated urbanized area in the United States, Los Angeles-Long Beach-Santa Ana, an urbanized area defined by the Census Bureau and had a population 11,789,487 as of the 2000 Census).
Based on commuting patterns, the U.S. Bureau of the Census also defines a wider region consisting of the Los Angeles metropolitan area plus two adjacent metropolitan areas. The area is known as the Los Angeles-Long Beach-Riverside Combined Statistical Area (CSA), with an estimated population of 17,786,419. This region is more commonly known as the Greater Los Angeles Area and includes three additional counties.
This wider region includes the second largest city in the United States, Los Angeles, and the counties of Los Angeles, Orange, Ventura, Riverside, and San Bernardino. The total land area of the metropolitan statistical area is 4,850 sq. mi (12,562 km2), while that of the combined statistical area is 33,955 sq. mi (87,945 km2).