The MSA is the most populous metropolitan area in the Western United States and second-most populous in the United States.

Anaheim–Santa Ana–Irvine, CA Metropolitan Division, coterminous with Orange County (2021 population 3,167,809).

Los Angeles–Long Beach-Glendale, CA Metropolitan Division, coterminous with Los Angeles County (2021 population 9,829,544).

The MSA is in turn made up of two 'metropolitan divisions': Office of Management and Budget as the Los Angeles–Long Beach–Anaheim, CA Metropolitan Statistical Area (MSA), with a 2021 population of 12,997,353. The Los Angeles metropolitan area is defined by the U.S.

Riverside-San Bernardino-Ontario, CA (MSA) In 2015, the Greater Los Angeles population was estimated to be about 18.7 million, making it the second largest metropolitan region in the country, behind New York, as well as one of the largest megacities in the world. census, the more narrowly defined Los Angeles metro area had a population of nearly 13 million residents. Throughout the 20th century, Greater Los Angeles was one of the fastest-growing regions in the United States, but growth has slowed since 2000. However, both form part of the Southern California Megalopolis which extends into Tijuana, Baja California, Mexico. Although San Diego–Tijuana borders the Greater Los Angeles area at San Clemente and Temecula, it is not part of it as the two urban areas are not geographically contiguous due to the presence of Camp Pendleton. It has a total area of 4,850 square miles (12,561 km 2). The Census Bureau designates the latter as the Los Angeles–Long Beach–Anaheim metropolitan statistical area, the fourth largest metropolitan area in the western hemisphere and the second-largest metropolitan area in the United States, by population. There are three contiguous component urban areas in Greater Los Angeles: the Inland Empire, which can be broadly defined as Riverside and San Bernardino counties the Ventura/Oxnard metropolitan area (Ventura County) and the Los Angeles metropolitan area (also known as Metropolitan Los Angeles or Metro LA) consisting of Los Angeles and Orange counties only. It is the third-largest metropolitan area by nominal GDP in the world with an economy exceeding $1 trillion in output, behind New York City and Tokyo. In addition to being the nexus of the global entertainment industry, including films, television, and recorded music, Greater Los Angeles is also an important center of international trade, education, media, business, tourism, technology, and sports. The contiguous urban area is 2,281 square miles (5,910 km 2), whereas the remainder mostly consists of mountain and desert areas.

The Los Angeles–Anaheim–Riverside combined statistical area covers 33,954 square miles (87,940 km 2), making it the largest metropolitan region in the United States by land area. It encompasses five counties in Southern California extending from Ventura County in the west to San Bernardino County and Riverside County in the east, with Los Angeles County in the center, and Orange County to the southeast. Greater Los Angeles is the second-largest metropolitan area in the United States, with a population of 18.5 million in 2021.

Los angeles california map