Chula Vista is a city in San Diego County, California, United States. It is also the second-largest city in the San Diego metropolitan area, the seventh largest city in Southern California, the fifteenth largest city in the state of California, and the 78th-largest city in the United States. The population was 275,487 as of the 2020 census, up from 243,916 as of the 2010 census. Located about halfway—7.5 miles (12.1 km)—between the two downtowns of San Diego and Tijuana in the South Bay, the city is at the center of one of the richest culturally diverse zones in the United States. Chula Vista is so named because of its scenic location between the San Diego Bay and coastal mountain foothills.

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.