El Cajon is a city in San Diego County, California. The population was 99,478 at the 2010 census and grew to 100,116 in 2011. Nestled in a valley surrounded by mountains, the city has acquired the nickname of "The Big Box". Its name originated similarly, from the Spanish phrase "el cajón", which means "the big box" or "the drawer".
According to the United States Census Bureau, the city has a total area of 14.4 square miles (37 km sq), all land. It is bordered by San Diego and La Mesa on the west, Spring Valley on the south, Santee on the north, and unincorporated San Diego County on the east. It includes the neighborhoods of Fletcher Hills, Bostonia, and Rancho San Diego.