There is a county in Southern California.
The Greater Los Angeles Area is the second-largest urban region in the United States , encompassing five counties in southern California , extending from Ventura County in the west to San Bernardino County and Riverside County on the east , with Los Angeles County in the center and Orange County to the southeast . Southern California . The region is traditionally described as eight counties , based on demographics and economic ties : Imperial , Los Angeles , Orange , Riverside , San Bernardino , San Diego , Santa Barbara , and Ventura . The 8-county and 10-county definitions are not used for the greater Southern California Megaregion , one of the 11 megaregions of the United States .