| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Santa Rosa | 1 | 179,437 | 177,938 | 0% | 4,218 | 43 | City |
| Petaluma | 2 | 59,609 | 59,752 | -0.13% | 4,135 | 14 | City |
| Rohnert Park | 3 | 44,902 | 44,463 | 0.2% | 6,163 | 7 | City |
| Windsor | 4 | 25,753 | 26,344 | -0.43% | 3,463 | 7 | Town |
| Healdsburg | 5 | 11,137 | 11,350 | -0.31% | 2,520 | 4 | City |
| Sonoma | 6 | 10,505 | 10,726 | -0.3% | 3,828 | 3 | City |
| Cloverdale | 7 | 8,641 | 9,009 | -0.69% | 2,569 | 3 | City |
| Sebastopol | 8 | 7,509 | 7,592 | -0.31% | 3,990 | 2 | City |
| Cotati | 9 | 7,299 | 7,600 | -0.65% | 3,895 | 2 | City |
Santa Rosa is the largest city in Sonoma County, with a population of 179,437.
Cotati is the smallest city in Sonoma County, with a population of 7,299.
There are 9 cities in Sonoma County, California.