Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Concord | 1 | 121,324 | 125,286 | -0.81% | 3,969 | 30.6 | City |
| Antioch | 2 | 117,668 | 115,379 | 0.49% | 4,034 | 29.2 | City |
| Richmond | 3 | 113,409 | 116,196 | -0.61% | 3,775 | 30.0 | City |
| San Ramon | 4 | 84,446 | 86,377 | -0.57% | 4,210 | 20.1 | City |
| Pittsburg | 5 | 75,619 | 76,354 | -0.24% | 4,278 | 17.7 | City |
| Walnut Creek | 6 | 68,804 | 70,196 | -0.5% | 3,482 | 19.8 | City |
| Brentwood | 7 | 65,350 | 64,453 | 0.34% | 4,396 | 14.9 | City |
| Oakley | 8 | 46,521 | 43,480 | 1.66% | 2,932 | 15.9 | City |
| Danville | 9 | 42,812 | 43,560 | -0.43% | 2,368 | 18.1 | Town |
| Martinez | 10 | 36,128 | 37,195 | -0.73% | 2,858 | 12.6 | City |
| Pleasant Hill | 11 | 33,534 | 34,604 | -0.79% | 4,740 | 7.1 | City |
| San Pablo | 12 | 30,969 | 32,089 | -0.9% | 11,802 | 2.6 | City |
| Hercules | 13 | 26,737 | 26,117 | 0.58% | 4,169 | 6.4 | City |
| El Cerrito | 14 | 25,422 | 25,941 | -0.51% | 6,923 | 3.7 | City |
| Lafayette | 15 | 24,933 | 25,392 | -0.46% | 1,660 | 15.0 | City |
| Bay Point | 16 | 24,917 | 25,378 | 1.03% | 3,878 | 6.4 | CDP |
| Orinda | 17 | 19,314 | 19,514 | -0.26% | 1,503 | 12.9 | City |
| Pinole | 18 | 18,306 | 19,005 | -0.95% | 3,587 | 5.1 | City |
| Moraga | 19 | 16,436 | 16,880 | -0.67% | 1,737 | 9.5 | Town |
| El Sobrante | 20 | 15,968 | 14,779 | 1.49% | 5,158 | 3.1 | CDP |
| Discovery Bay | 21 | 15,697 | 15,904 | 1.07% | 2,807 | 5.6 | CDP |
| Alamo | 22 | 14,319 | 13,864 | -0.13% | 1,459 | 9.8 | CDP |
| El Sobrante | 23 | 12,028 | 13,096 | -0.41% | 1,663 | 7.2 | CDP |
| Blackhawk | 24 | 10,833 | 10,590 | 0.98% | 1,876 | 5.8 | CDP |
| Clayton | 25 | 10,652 | 11,058 | -0.95% | 2,774 | 3.8 | City |
| Rodeo | 26 | 9,443 | 10,023 | 0.57% | 2,520 | 3.7 | CDP |
| Contra Costa Centre | 27 | 8,031 | 6,667 | 7.68% | 12,608 | 0.6 | CDP |
| Camino Tassajara | 28 | 6,912 | 5,870 | 5.13% | 5,417 | 1.3 | CDP |
| Saranap | 29 | 6,292 | 6,027 | 1.26% | 5,544 | 1.1 | CDP |
| El Cerrito | 30 | 5,366 | 5,269 | 0.36% | 2,062 | 2.6 | CDP |
| Pacheco | 31 | 5,267 | 4,775 | 2.19% | 7,013 | 0.8 | CDP |
| Tara Hills | 32 | 5,215 | 4,915 | 0.13% | 7,819 | 0.7 | CDP |
| North Richmond | 33 | 3,737 | 4,258 | 0.05% | 2,688 | 1.4 | CDP |
| Crockett | 34 | 3,654 | 3,205 | 1.11% | 3,441 | 1.1 | CDP |
| Rollingwood | 35 | 3,569 | 3,612 | 1.22% | 20,630 | 0.2 | CDP |
| East Richmond Heights | 36 | 3,286 | 3,473 | 0.03% | 5,666 | 0.6 | CDP |
| Reliez Valley | 37 | 3,205 | 3,321 | 0.25% | 1,358 | 2.4 | CDP |
| Vine Hill | 38 | 3,126 | 3,228 | -1.45% | 2,081 | 1.5 | CDP |
| Bayview | 39 | 2,658 | 2,754 | 2.47% | 8,715 | 0.3 | CDP |
| Montalvin Manor | 40 | 2,082 | 2,490 | -2.62% | 6,486 | 0.3 | CDP |
| Byron | 41 | 2,025 | 2,057 | 2.74% | 311 | 6.5 | CDP |
| Bethel Island | 42 | 1,969 | 2,015 | -0.61% | 375 | 5.3 | CDP |
| Knightsen | 43 | 1,659 | 1,100 | 0.42% | 199 | 8.4 | CDP |
| Shell Ridge | 44 | 1,055 | 1,081 | 0.67% | 2,453 | 0.4 | CDP |
| Castle Hill | 45 | 962 | 1,164 | -2.43% | 1,644 | 0.6 | CDP |
| Norris Canyon | 46 | 954 | 790 | 0% | 264 | 3.6 | CDP |
| North Gate | 47 | 937 | 740 | 2.07% | 1,275 | 0.7 | CDP |
| Acalanes Ridge | 48 | 932 | 875 | -1.48% | 2,022 | 0.5 | CDP |
| Alhambra Valley | 49 | 916 | 1,051 | 0% | 568 | 1.6 | CDP |
| Clyde | 50 | 728 | 737 | 0.41% | 5,163 | 0.1 | CDP |
| Diablo | 51 | 708 | 834 | -4.32% | 519 | 1.4 | CDP |
| Port Costa | 52 | 261 | 242 | 1.95% | 1,652 | 0.2 | CDP |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Concord is the largest city in Contra Costa County.
Port Costa is the smallest city in Contra Costa County.
There are 52 cities in Contra Costa County, California.