How many people live in Contra Costa County, CA?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 1.17 million people living in Contra Costa County, CA. That makes Contra Costa County the 41st-most populous county in the US. It is also the ninth-largest in California, accounting for 3% of the state’s population.
1.17M
population of Contra Costa County, CA (2024)
3%
County share of the California population (2024)
About 1.17 million people lived in Contra Costa County, CA in 2024.
Population estimates, 2000–2024
What are Contra Costa County, CA’s age demographics?
About 211,400 Contra Costa County, CA residents are aged 65 and older in 2024. That represents 18% of its population. For comparison, the age group represents 16.6% of California’s population and 18% in the US overall.
Another 251,500 Contra Costa County residents, or 21.4% of the population, were children under 18. For comparison, the age group represents 21.4% of California’s population and 21.6% in the US overall.
A higher share of Contra Costa County, CA's population is aged 45–64 than the US as a whole.
Population estimates by age group, (2024)
What are Contra Costa County, CA’s racial and ethnic demographics?
Hispanic residents make up 28.2% of the Contra Costa County, CA population, higher than the national share of 20%. Contra Costa County, CA also has a larger share of people identifying as non-Hispanic Asian (20.6%) than the US overall (6.5%).
In contrast, Contra Costa County’s non-Hispanic white population accounts for 37.6%, below the 57.5% nationwide, and the non-Hispanic Black or African American population makes up 8.3% of the county, compared with 12.6% nationally.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.
Contra Costa County, CA has a higher share of a non-Hispanic Asian population than California as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Contra Costa County, CA is Concord with about 124,000 residents in 2024.
Cities and towns in Contra Costa County, CA ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Concord | 124,016 |
| 2. | Antioch | 118,453 |
| 3. | Richmond | 115,353 |
| 4. | San Ramon | 85,924 |
| 5. | Pittsburg | 77,131 |
| 6. | Walnut Creek | 70,817 |
| 7. | Brentwood | 66,286 |
| 8. | Oakley | 47,158 |
| 9. | Danville | 43,410 |
| 10. | Martinez | 37,006 |
Keep exploring
Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
