Rancho San Diego, California Rancho San Diego, California Rancho San Diego is a census-designated place (CDP) in San Diego County, California. The population was 21,208 at the 2010 census, up from 20,155 at the 2000 census. The area was developed as subdivisions beginning in the 1970s. Rancho San Diego is located at (32.765985, -116.921477). According to the United States Census Bureau, the CDP has a total area of , all land. The chance of earthquake damage in Rancho San Diego is much lower than California average and is much higher than the national average. The risk of tornado damage in Rancho San Diego is
San Diego Alcalá, founded in 1769, formed the first European settlement in what is now California. In 1821, San Diego became part of the newly independent Mexico, which reformed as the First Mexican Republic two years later. California became part of the United States in 1848 following the Mexican–American War and was admitted to the union as a state in 1850. The city is the seat of San Diego County and is the economic center of the region as well as the San Diego–Tijuana metropolitan area. San Diego's main economic engines are military and defense-related activities, tourism, international trade, and manufacturing. The