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 County, California of the Treaty of Guadalupe Hidalgo in 1848, ending the Mexican–American War. This treaty designated the new border as terminating at a point on the Pacific Ocean coast which would result in the border passing one Spanish league south of the southernmost portion of San Diego Bay, thus ensuring that the United States received all of this natural harbor. San Diego County was one of the original counties of California, created at the time of California statehood in 1850. At the time of its establishment in 1850, San Diego County was relatively large, and included all of southernmost California south