How many square miles is san Diego county?
The total area for the county of San Diego in California is 4,526 square miles. Land makes up most of this area covering 4,207 square miles while water covers just 319 square miles of the county.
There is no strict definition of "Southern California." But if you want to count LA County, San Diego County, Orange County, Riverside County, San Bernardino County, Ventura County, and Santa Barbara County; then Southern California is about 40,892 square miles. If you add in Kern County, San Luis Obispo County, and Imperial County...then Southern California is about 56,512 square miles.