Imperial County is a county located on the southeast border of the U.S. state of California. As of the 2020 census, the population was 179,702, making it the least populous county in Southern California. The county seat and largest city is El Centro. Imperial is the most recent California county to be established, as it was created in 1907 out of portions of San Diego County.

Southern California 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 as well as the Inland Empire. The region generally contains ten of California's 58 counties: Imperial, Kern, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, San Luis Obispo and Ventura counties.