Contra Costa County, California Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 9th-largest in California
The population of Contra Costa County, California is 1,161,458 as of the 2023 American Community Survey, making it the 9th-largest county in California. The median household income is $125,727, the median home value is $830,800, and the median age is 40.3.
The population of Contra Costa County has grown 11.4% since 2010 (1,052,516 → 1,172,607), a +0.77% annualized rate.
1,161,458
Population
+0.77%
Annual growth
1620
People / sq mi
$125,727
Median Income
$830,800
Median Home Value
Contra Costa County covers 717 sq mi of land at 1620.1 people per square mile.
About Contra Costa County, CA
Contra Costa County is a county in California with a population of 1,161,458. It ranks #9 among counties in California by population. The median age is 40.3, older than the national median. The population is 49.2% male and 50.8% female.
The median household income in Contra Costa County is $125,727, above the US median of $74,580. 5.7% of residents live below the federal poverty level. Home values sit at a median of $830,800, with monthly rent averaging $2,322. The homeownership rate of 67.7% is higher than the national rate of 64.8%.
Educational attainment in Contra Costa County reflects 44.9% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 19.2% of workers primarily work from home, noticeably above the national work-from-home rate of 14.2%. The average commute is 36.0 minutes each way.
Contra Costa County Population History (2010-2024)
The county of Contra Costa County had a population of 1,052,516 in 2010 and 1,172,607 in 2024, a 11.4% growth over 14 years. The peak was 1,172,607 in 2024. Average annual growth rate: 0.78%.
1,172,607
Population (2024)
1,052,516
Population (2010)
1,172,607
Peak (2024)
0.78%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 1,052,516 |
| 2011 | 1,065,361 |
| 2012 | 1,077,439 |
| 2013 | 1,093,253 |
| 2014 | 1,108,665 |
| 2015 | 1,124,148 |
| 2016 | 1,137,259 |
| 2017 | 1,145,623 |
| 2018 | 1,150,840 |
| 2019 | 1,152,883 |
| 2020 | 1,166,165 |
| 2021 | 1,163,813 |
| 2022 | 1,160,296 |
| 2023 | 1,162,179 |
| 2024 | 1,172,607 |
Race & Ethnicity
| White | 43.5% |
| Black or African American | 8.5% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.6% |
| Two or More Races | 0.1% |
Age & Sex
40.3
Median Age
50.8%
Female
49.2%
Male
16.7%
Age 65+
Age Distribution
Children (under 15): 18.0% · Seniors (65+): 16.7%
Income & Poverty
| Median household income | $125,727+$29,393 vs state |
| Mean household income | $172,107 |
| Per-capita income | $61,727 |
| Poverty rate | 5.7%-2.7% vs state |
| Unemployment rate | 3.8% |
| Employment-to-population | 61.2% |
Top Industries by Employment
The largest employment sector in Contra Costa County is professional & business services, accounting for 22.7% of workers.
How residents commute
6.5%
Drive alone
1.8%
Carpool
60.8%
Public transit
19.2%
Work from home
36.0 min
Avg commute
Housing
$830,800+$135,400 vs state
Median home value
$2,322
Median rent
67.7%
Homeownership rate
426,585
Total housing units
96.5%
Occupied
3.5%
Vacant
32.3%
Renter-occupied
Social & access
95.2%
With health insurance
97.5%
With broadband internet
16.4%
Foreign-born
4.4%
Veterans (18+)
11.2%
With a disability
63.0%
Speak language other than English at home
Education
89.6%
High School+
44.9%
Bachelor's+
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County rankings
Common questions about Contra Costa County, CA
Frequently Asked Questions
Contra Costa County, California has a population of 1,161,458 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 9th-largest county in California. Population density is 1620 people per square mile.
The population of Contra Costa County has grown 11.4% since 2010 (1,052,516 → 1,172,607), a +0.77% annualized rate.
The median household income in Contra Costa County, California is $125,727, with mean (average) household income of $172,107 and per-capita income of $61,727. 5.7% of residents live below the federal poverty level.
In Contra Costa County, the largest racial and ethnic groups are White (43.5%), Black or African American (8.5%), Hispanic or Latino (2.6%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Contra Costa County, California is 40.3 years. Residents are 50.8% female and 49.2% male.
The median home value in Contra Costa County is $830,800 and median monthly rent is $2,322. 67.7% of occupied housing units are owner-occupied. The county has 426,585 total housing units, 3.5% of which are vacant.
The largest employment sector in Contra Costa County, California is professional, scientific, and management services, employing 22.7% of workers. The unemployment rate is 3.8%.
Los Angeles is among the largest cities associated with Contra Costa County, California, with a population of 3,857,897.
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.