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
Housing cost is the defining feature of Contra Costa County: the median home is valued at $830,800. With 1,161,458 residents, Contra Costa County is a county in California. It is the #9-largest of all counties in California nationally.
Income is a real outlier — the median household pulls in $125,727, putting Contra Costa County near the top of US counties. Only 5.7% of residents live in poverty, below the national 12.4%. Home prices are steep, with the typical property valued at $830,800, with typical rent around $2,322.
Contra Costa County is among the best-educated US counties: 44.9% of adults 25 and older hold a bachelor’s degree, above the national 35.0%. Working from home is common here: 19.2% of workers do so, above the national 14.0%, and the average commute runs about 36 minutes each way.
High housing values reframe the income picture in Contra Costa County — even solid earnings stretch less against home prices and rents at this level.
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.