California Population 2024 By County By State. Data for fivethirtyeight's previous favorability, presidential approval and national 2024 republican primary averages is available for download here. The most populated counties in california are los angeles county with 9,663,345, san diego county at 3,269,973, orange county with 3,135,755, riverside county at 2,492,442,.

Not surprisingly, california ‘s los angeles county is the largest county in the state, as well as the nation, with a huge population of 10,150,558 that. California contains the second largest city (los angeles), 3 of the largest 10 cities (los angeles, san diego, and san jose), and the largest county (los angeles county) in the united states.