52 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Concord | 1 | 120,334 | 125,286 | -0.82% | 3,937 | 30.57 | City |
| Antioch | 2 | 118,240 | 115,379 | 0.49% | 4,053 | 29.17 | City |
| Richmond | 3 | 112,712 | 116,196 | -0.61% | 3,752 | 30.04 | City |
| San Ramon | 4 | 83,963 | 86,377 | -0.57% | 4,186 | 20.06 | City |
| Pittsburg | 5 | 75,435 | 76,354 | -0.24% | 4,268 | 17.68 | City |
| Walnut Creek | 6 | 68,456 | 70,196 | -0.51% | 3,464 | 19.76 | City |
| Brentwood | 7 | 65,574 | 64,453 | 0.34% | 4,411 | 14.87 | City |
| Oakley | 8 | 47,281 | 43,480 | 1.63% | 2,980 | 15.87 | City |
| Danville | 9 | 42,625 | 43,560 | -0.44% | 2,358 | 18.08 | Town |
| Martinez | 10 | 35,861 | 37,195 | -0.74% | 2,836 | 12.64 | City |
| Pleasant Hill | 11 | 33,267 | 34,604 | -0.8% | 4,702 | 7.08 | City |
| San Pablo | 12 | 30,689 | 32,089 | -0.9% | 11,696 | 2.62 | City |
| Hercules | 13 | 26,892 | 26,117 | 0.58% | 4,193 | 6.41 | City |
| El Cerrito | 14 | 25,292 | 25,941 | -0.51% | 6,888 | 3.67 | City |
| Bay Point | 15 | 25,171 | 25,378 | 1.02% | 3,917 | 6.43 | CDP |
| Lafayette | 16 | 24,818 | 25,392 | -0.46% | 1,652 | 15.02 | City |
| Orinda | 17 | 19,264 | 19,514 | -0.26% | 1,499 | 12.85 | City |
| Pinole | 18 | 18,131 | 19,005 | -0.96% | 3,552 | 5.10 | City |
| Moraga | 19 | 16,325 | 16,880 | -0.68% | 1,726 | 9.46 | Town |
| El Sobrante | 20 | 16,204 | 14,779 | 1.48% | 5,234 | 3.10 | CDP |
| Discovery Bay | 21 | 15,864 | 15,904 | 1.06% | 2,837 | 5.59 | CDP |
| Alamo | 22 | 14,301 | 13,864 | -0.13% | 1,457 | 9.82 | CDP |
| El Sobrante | 23 | 11,978 | 13,096 | -0.42% | 1,656 | 7.23 | CDP |
| Blackhawk | 24 | 10,939 | 10,590 | 0.98% | 1,894 | 5.78 | CDP |
| Clayton | 25 | 10,551 | 11,058 | -0.95% | 2,748 | 3.84 | City |
| Rodeo | 26 | 9,498 | 10,023 | 0.58% | 2,535 | 3.75 | CDP |
| Contra Costa Centre | 27 | 8,605 | 6,667 | 7.15% | 13,509 | 0.64 | CDP |
| Camino Tassajara | 28 | 7,248 | 5,870 | 4.86% | 5,680 | 1.28 | CDP |
| Saranap | 29 | 6,369 | 6,027 | 1.22% | 5,611 | 1.14 | CDP |
| El Cerrito | 30 | 5,385 | 5,269 | 0.35% | 2,070 | 2.60 | CDP |
| Pacheco | 31 | 5,380 | 4,775 | 2.15% | 7,164 | 0.75 | CDP |
| Tara Hills | 32 | 5,221 | 4,915 | 0.12% | 7,828 | 0.67 | CDP |
| North Richmond | 33 | 3,738 | 4,258 | 0.03% | 2,689 | 1.39 | CDP |
| Crockett | 34 | 3,694 | 3,205 | 1.09% | 3,478 | 1.06 | CDP |
| Rollingwood | 35 | 3,612 | 3,612 | 1.2% | 20,879 | 0.17 | CDP |
| East Richmond Heights | 36 | 3,286 | 3,473 | 0% | 5,666 | 0.58 | CDP |
| Reliez Valley | 37 | 3,212 | 3,321 | 0.22% | 1,361 | 2.36 | CDP |
| Vine Hill | 38 | 3,081 | 3,228 | -1.44% | 2,051 | 1.50 | CDP |
| Bayview | 39 | 2,723 | 2,754 | 2.45% | 8,928 | 0.30 | CDP |
| Byron | 40 | 2,078 | 2,057 | 2.62% | 319 | 6.52 | CDP |
| Montalvin Manor | 41 | 2,025 | 2,490 | -2.74% | 6,308 | 0.32 | CDP |
| Bethel Island | 42 | 1,957 | 2,015 | -0.61% | 373 | 5.25 | CDP |
| Knightsen | 43 | 1,666 | 1,100 | 0.42% | 199 | 8.36 | CDP |
| Shell Ridge | 44 | 1,061 | 1,081 | 0.57% | 2,467 | 0.43 | CDP |
| North Gate | 45 | 955 | 740 | 1.92% | 1,299 | 0.73 | CDP |
| Norris Canyon | 46 | 953 | 790 | -0.1% | 264 | 3.61 | CDP |
| Castle Hill | 47 | 938 | 1,164 | -2.49% | 1,603 | 0.58 | CDP |
| Acalanes Ridge | 48 | 917 | 875 | -1.61% | 1,989 | 0.46 | CDP |
| Alhambra Valley | 49 | 915 | 1,051 | -0.11% | 567 | 1.61 | CDP |
| Clyde | 50 | 732 | 737 | 0.55% | 5,191 | 0.14 | CDP |
| Diablo | 51 | 676 | 834 | -4.52% | 496 | 1.36 | CDP |
| Port Costa | 52 | 266 | 242 | 1.92% | 1,684 | 0.16 | CDP |
Concord is the largest city in Contra Costa County, with a population of 120,334.
Port Costa is the smallest city in Contra Costa County.
There are 52 cities in Contra Costa County, California.