Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area (the second most populous urban agglomeration in the United States) as well as the Inland Empire (another large metropolitan area). The region generally contains ten of California's 58 counties: Los Angeles, San Diego, Orange, Riverside, San Bernardino, Kern, Ventura, Santa Barbara, San Luis Obispo, and Imperial counties.

Although geographically smaller than Northern California in land area, Southern California has a higher population, with 23.76 million residents as of the 2020 census. The sparsely populated desert region of California occupies a significant portion (part of which has even been proposed to be split into a new county due to cultural, economic and geographic differences relative to the rest of the more urban region) of the area: the Colorado Desert, along with the Colorado River, is located on Southern California's eastern border with Arizona, and the Mojave Desert shares a border with Nevada to the northeast. Southern California's southern border with Baja California is part of the Mexico–United States border.