California Cities By Population 2024 Population. At the last official united states census carried out in 2020, the population of california was declared at 39,538,223 which makes the state the most populous by a wide margin over. California has experienced significant population changes since 2000.

California has the largest population in usa with population over 40 million, which accounts for 12% of the usa population. This report provides population estimates for january 1, 2021 through january 1, 2023 and provisional population estimates for january 1, 2024, for the state, counties, and cities.