9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Colusa | 1 | 6,632 | 6,416 | 0.65% | 1,521 | 4 | City |
| Williams | 2 | 5,611 | 5,546 | 0.23% | 1,134 | 5 | City |
| Arbuckle | 3 | 3,083 | 3,368 | 0.13% | 1,753 | 2 | CDP |
| Maxwell | 4 | 1,200 | 1,256 | 0.5% | 558 | 2 | CDP |
| Princeton | 5 | 370 | 337 | 1.09% | 253 | 1 | CDP |
| College City | 6 | 356 | 205 | 1.14% | 121 | 3 | CDP |
| Grimes | 7 | 346 | 462 | -0.86% | 153 | 2 | CDP |
| Lodoga | 8 | 202 | 184 | 0% | 60 | 3 | CDP |
| Stonyford | 9 | 65 | 76 | -8.45% | 46 | 1 | CDP |
Colusa is the largest city in Colusa County, with a population of 6,632.
Stonyford is the smallest city in Colusa County, with a population of 65.
There are 9 cities in Colusa County, California.