Imperial Beach is a residential beach city in San Diego County, California, with a population of 26,137 at the 2020 United States census, down from 26,324 at the 2010 census. The city is the southernmost city in California and the West Coast of the United States. It is in the South Bay area of San Diego County, 14.1 miles (22.7 km) south of downtown San Diego and 5 miles (8 km) northwest of downtown Tijuana, Mexico.

The South Bay, also known as South County, is a region in southwestern San Diego County, California consisting of the cities and unincorporated communities of Bonita, Chula Vista, East Otay Mesa, Imperial Beach, Lincoln Acres, National City, and South San Diego.