Contra Costa County, California
Located in California, Contra Costa County has a population of 1,165,012 residents and a median age of 40.5 years, making it the #39 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 8.4%. The median home value is $866,800, and the median household income is $127,229, which is 69% above the national median.
Demographics
Contra Costa County has a population of 1,165,012, making it the #39 most populous county in the US. The median age is 40.5 years, which is 4.1% above the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in Contra Costa County is $127,229, ranking #36 out of 3,222 counties — 69.3% above the national median. The poverty rate is 8.4% and unemployment stands at 6.5%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Contra Costa County is $866,800 (+207.5% vs national). Renters pay a median of $2,375/mo and the homeownership rate is 68.0%.
Median Home Value Trend
Rankings →Household Type
Education
In Contra Costa County, 45.2% of adults age 25+ hold a bachelor's degree or higher, which is 34.2% above the national average, ranking #171 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Contra Costa County is 81.2 years. 15.5% of adults report poor or fair health and 5.2% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
10.5% of adults in Contra Costa County smoke , 28.4% are obese , and 21.3% report excessive drinking. The drug overdose death rate is 21.7 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Contra Costa County is 5.6 per 100,000 and the suicide rate is 9.4 per 100,000. Motor vehicle deaths occur at a rate of 8.8 per 100,000.
Homicide Rate Trend
Families & Children
10.1% of children in Contra Costa County live in poverty and the infant mortality rate is 3.5 per 1,000 live births. The teen birth rate is 7.2 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Contra Costa County is 75.1%. The mean commute time is 39.0 min, which is 41.3% above the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Contra Costa County voted Democratic with a margin of 37.9%. The vote was 67.3% Dem / 29.4% Rep. Compared to 2020, the margin shifted 7.4 toward Republicans .
Vote Share Over Time
About Contra Costa County, California
Contra Costa County, California has a total population of 1,165,012, making it the 39th most populous county in the United States. The median age in Contra Costa County is 40.5 years, which is 4.1% above the national median of 38.9 years.
The median household income in Contra Costa County is $127,229, which ranks #36 of 3,222 counties nationwide. This is 69.3% above the national median of $75,149. The poverty rate is 8.4%, lower than the national rate of 12.6%. The unemployment rate stands at 6.5%.
The median home value in Contra Costa County is $866,800, 207.5% above the national median. Renters in Contra Costa County pay a median gross rent of $2,375 per month. The homeownership rate is 68.0%, compared to the national rate of 64.4%.
In Contra Costa County, 45.2% of residents aged 25 and older hold a bachelor's degree or higher, 34.2% above the national average of 33.7%. Health insurance coverage stands at 95.4% of the population. The average commute time for workers is 39.0 min.
Contra Costa County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 38.1% of the population, followed by Hispanic or Latino (27.6%) and Asian (non-Hispanic) (18.6%).
All data for Contra Costa County, California comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.