11 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| San Rafael | 1 | 59,370 | 61,143 | -0.49% | 3,579 | 17 | City |
| Novato | 2 | 51,893 | 53,146 | -0.4% | 1,896 | 27 | City |
| Mill Valley | 3 | 13,754 | 14,203 | -0.54% | 2,876 | 5 | City |
| Larkspur | 4 | 12,693 | 13,035 | -0.45% | 4,232 | 3 | City |
| San Anselmo | 5 | 12,560 | 12,815 | -0.33% | 4,695 | 3 | Town |
| Corte Madera | 6 | 9,906 | 10,206 | -0.5% | 3,135 | 3 | Town |
| Tiburon | 7 | 8,830 | 9,138 | -0.57% | 1,967 | 4 | Town |
| Fairfax | 8 | 7,417 | 7,593 | -0.39% | 3,329 | 2 | Town |
| Sausalito | 9 | 6,984 | 7,257 | -0.64% | 3,959 | 2 | City |
| Ross | 10 | 2,280 | 2,331 | -0.35% | 1,463 | 2 | Town |
| Belvedere | 11 | 2,057 | 2,126 | -0.53% | 3,963 | 1 | City |
San Rafael is the largest city in Marin County, with a population of 59,370.
Belvedere is the smallest city in Marin County, with a population of 2,057.
There are 11 cities in Marin County, California.