Contra Costa County Flag

Contra Costa County

State:
California
County Seat:
Martinez

Contra Costa County's estimated 2026 population is 1,170,606 with a growth rate of 0.05% in the past year according to the most recent United States census data. Contra Costa County is the 9th largest county in California. The 2010 population was 1,052,516 and has seen a growth of 11.22% since that time.

1,170,606
Total Population
1,633
Population Density (mi²)
9
Population Rank (State)
536 0.05%
Annual Population Growth

Contra Costa County Population

Demographics

Economics and Income Statistics