Calexico is a city in southern Imperial County, California, United States. As of the 2020 census, Calexico had a population of 38,633. Situated on the Mexican border, it is linked economically with the much larger city of Mexicali, the capital of the Mexican state of Baja California. It is about 122 miles (196 km) east of San Diego and 62 miles (100 km) west of Yuma, Arizona. Calexico, along with six other incorporated Imperial County cities, forms part of the larger populated area known as the Imperial Valley. First explored by Europeans in the 18th century, Calexico began as a small tent community which was ultimately incorporated in 1908.