El Centro is a city in and county seat of Imperial County, California, the largest city in the Imperial Valley, east anchor of the Southern California Border Region, and the core urban area and principal city of the El Centro metropolitan area which encompasses all of Imperial County. El Centro is also the largest American city to lie entirely below sea level. The city, located in southeastern California, is near the major Southern California city of San Diego and the Mexican city of Mexicali.Founded in 1906, W. F. Holt and C.A. Barker purchased the land on which El Centro was eventually built for about $40 per acre and invested $100,000 in improvements. As one historian of valley life put it, "in only five months El Centro went from a barley field to a city...". It is home to retail, transportation, wholesale, and agricultural industries. There are also two international border crossings nearby for commercial and noncommercial vehicles.