California State Population 2024. California is the most populous state in the united states, with a resident population of almost 40 million people. The population of california in 2021 was 39,145,060, a 0.91% decline from 2020.

By far the most populous state in the united states is california, which has more than 40 million residents and comprises nearly 12% of the country’s total population. Usafacts uses census data to break down the population of california by race, age, and more.