Constituent metropolitan areas
Southern California includes the heavily built-up urban area which stretches along the Pacific coast from Ventura through Greater Los Angeles down to Greater San Diego (the contiguous urban area in fact continuing into Tijuana, Mexico), and inland to the Inland Empire and Coachella Valley (Palm Springs area). It encompasses eight metropolitan areas (MSAs), three of which together form the Greater Los Angeles Combined Statistical Area (CSA) with over 18 million people, the second-biggest CSA after the New York CSA. These three MSAs are: the Los Angeles metropolitan area (Los Angeles and Orange counties, with 13.3 million people), the Inland Empire ((Riverside and San Bernardino counties, including the Coachella Valley cities, with 4.3 million people), and the Oxnard–Thousand Oaks–Ventura metropolitan area (0.8 million people). In addition, Southern California contains the San Diego metropolitan area with 3.3 million people, Bakersfield metro area with 0.9 million, and the Santa Barbara, San Luis Obispo, and El Centro (Imperial County) metropolitan areas.
The Southern California Megaregion (or megalopolis) is larger still, extending east into Las Vegas, Nevada and south across the Mexican border into Tijuana.