Demographics
Contra Costa County Demographic Quick Facts
2020 Decennial Census Results
On August 12, 2021 the Census Bureau released the first local level 2020 Census data. Initial analysis is provided below. The State Department of Finance has additional detailed tables available.
Visit the State Department of Finance Census 2020 webpage.
Data Profile for all Cities, Towns, and Unincorporated Census Designated Places (PDF)
2020 County Population: 1,165,927
Contra Costa County saw an increase of 116,902 people (10% increase)
Source: 2020 Decennial Census
2020 Population by Supervisorial District
During the once a decade redistricting process, districts must be redrawn so that each district is substantially equal in population. In California, Redistricting must be done using the California Redistricting data, which is based on the 2020 Census data.
Equal Proportion based on 2020 Census: 233,185 people.
The current spread is 8.08%, this is the difference between the highest and lowest percentage from the mean.
The percentage deviation from the mean is shown in parenthesis below.
District 1 Population: 224,726
8,459 under (-3.63%)
District 2 Population: 243,565
10,380 over (4.45%)
District 3 Population: 239,825
6,640 over (2.85%)
District 4 Population: 229,384
3,837 under (-1.65%)
District 5 Population: 228,463
4,722 under (-2.03%)
2020 City Population and Growth Rate
| City | 2020 Population | 2010 Population | Growth Rate |
|---|---|---|---|
| Brentwood city | 64,292 | 51,481 | 19.9% |
| Oakley city | 43,357 | 35,432 | 18.3% |
| Pittsburg city | 76,416 | 63,264 | 17.2% |
| San Ramon city | 84,605 | 72,148 | 14.7% |
| Antioch city | 115,291 | 102,372 | 11.2% |
| Richmond city | 116,448 | 103,701 | 10.9% |
| Orinda city | 19,514 | 17,643 | 9.6% |
| San Pablo city | 32,127 | 29,139 | 9.3% |
| El Cerrito city | 25,962 | 23,549 | 9.3% |
| Walnut Creek city | 70,127 | 64,173 | 8.5% |
| Hercules city | 26,016 | 24,060 | 7.5% |
| Lafayette city | 25,391 | 23,893 | 5.9% |
| Moraga town | 16,870 | 16,016 | 5.1% |
| Pleasant Hill city | 34,613 | 33,152 | 4.2% |
| Martinez city | 37,287 | 35,824 | 3.9% |
| Danville town | 43,582 | 42,039 | 3.5% |
| Pinole city | 19,022 | 18,390 | 3.3% |
| Concord city | 125,410 | 122,067 | 2.7% |
| Clayton city | 11,070 | 10,897 | 1.6% |
2010 Population: 1,049,025
source: 2010 Decennial Census
2020 Countywide Population Estimate: 1,153,561
2020 Unincorporated County Population Estimate: 174,257
Source: California Department of Finance Demographic Research Unit
Explore Department of Finance Population Estimates for Cities, County, and the State
Population Characteristic Data
The Census Bureau's American Community Survey (ACS) provides detailed information about population characteristics. Explore Census ACS Data at data.census.gov
Learn More About ACS data - US Census Bureau's ACS Users Guide