33 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| San Rafael | 1 | 58,500 | 61,137 | -0.89% | 3,527 | 16.59 | City |
| Novato | 2 | 50,775 | 53,142 | -0.92% | 1,855 | 27.37 | City |
| Mill Valley | 3 | 13,519 | 14,201 | -1% | 2,827 | 4.78 | City |
| Tamalpais-Homestead Valley | 4 | 12,561 | 12,331 | 0.97% | 2,681 | 4.68 | CDP |
| Larkspur | 5 | 12,295 | 13,029 | -1.18% | 4,100 | 3 | City |
| San Anselmo | 6 | 12,291 | 12,808 | -0.83% | 4,595 | 2.67 | Town |
| Corte Madera | 7 | 9,772 | 10,209 | -0.88% | 3,092 | 3.16 | Town |
| Tiburon | 8 | 8,651 | 9,138 | -1.11% | 1,927 | 4.49 | Town |
| Kentfield | 9 | 7,641 | 7,423 | 1.02% | 2,524 | 3.03 | CDP |
| Fairfax | 10 | 7,304 | 7,586 | -0.76% | 3,278 | 2.23 | Town |
| Sausalito | 11 | 6,865 | 7,254 | -1.12% | 3,892 | 1.76 | City |
| Lucas Valley-Marinwood | 12 | 6,394 | 6,738 | 0.31% | 1,116 | 5.73 | CDP |
| Santa Venetia | 13 | 3,658 | 3,891 | -1.14% | 998 | 3.66 | CDP |
| Marin City | 14 | 3,607 | 3,040 | 1.78% | 6,717 | 0.54 | CDP |
| Sleepy Hollow | 15 | 2,877 | 2,366 | 1.16% | 970 | 2.97 | CDP |
| Ross | 16 | 2,256 | 2,341 | -0.75% | 1,448 | 1.56 | Town |
| Fairfax | 17 | 2,220 | 1,778 | 7.14% | 2,332 | 0.95 | CDP |
| Belvedere | 18 | 1,998 | 2,127 | -1.28% | 3,850 | 0.52 | City |
| Black Point-Green Point | 19 | 1,778 | 1,738 | 1.77% | 650 | 2.73 | CDP |
| Lagunitas-Forest Knolls | 20 | 1,729 | 1,874 | -0.35% | 407 | 4.25 | CDP |
| Inverness | 21 | 1,510 | 1,497 | 0.94% | 236 | 6.40 | CDP |
| Woodacre | 22 | 1,399 | 1,464 | 0.21% | 779 | 1.80 | CDP |
| Bolinas | 23 | 1,195 | 1,223 | -2.29% | 205 | 5.83 | CDP |
| Petaluma Center | 24 | 1,061 | 1,020 | 7.17% | 905 | 1.17 | CDP |
| Alto | 25 | 646 | 818 | -0.62% | 5,127 | 0.13 | CDP |
| Dillon Beach | 26 | 482 | 309 | 2.99% | 162 | 2.98 | CDP |
| Muir Beach | 27 | 431 | 360 | 1.89% | 874 | 0.49 | CDP |
| San Geronimo | 28 | 422 | 176 | -0.47% | 280 | 1.51 | CDP |
| Stinson Beach | 29 | 306 | 583 | -6.71% | 343 | 0.89 | CDP |
| Point Reyes Station | 30 | 267 | 210 | -12.75% | 74 | 3.62 | CDP |
| Tomales | 31 | 172 | 160 | -1.15% | 518 | 0.33 | CDP |
| Bloomfield | 32 | 160 | 243 | -6.98% | 20 | 8.14 | CDP |
| Nicasio | 33 | 104 | 123 | 7.22% | 80 | 1.30 | CDP |
San Rafael is the largest city in Marin County, with a population of 58,500.
Nicasio is the smallest city in Marin County.
There are 33 cities in Marin County, California.