California Counties by Population (2026)

There are 58 counties in California.

Los Angeles County is the largest county in the state, with a population of 9,807,863. The most recent census shows that its population has decreased by 0.02% since the previous census.

A number of other California counties also boast relatively large populations for their state, though not able to match the density of Los Angeles County:

• San Diego County : 3,324,617
• Orange County : 3,202,179

California Counties with the Fewest Residents

The smallest county in California is Alpine County , with a population of just 1,045. This total represents a decrease of 0.1% since the last census count was performed.

Other small counties include:

• Sierra County : 2,979
• Modoc County : 8,341
• Mono County : 12,559

California Counties with Rapid Growth

Placer County , with its sizeable population of 452,268, has shown the largest population growth, with an increase of 0.1% since the last census.

San Joaquin County has also had relatively high population growth of 0.07% with 836,506 residents.

On the other hand, Lassen County has had the largest decrease in population, with its 27,344 current residents totalling 0.2% less than the previous census.