9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Yreka | 1 | 7,656 | 7,805 | -0.39% | 767 | 10 | City |
| Mount Shasta | 2 | 3,100 | 3,220 | -0.77% | 822 | 4 | City |
| Weed | 3 | 2,576 | 2,859 | -2.16% | 535 | 5 | City |
| Dunsmuir | 4 | 1,596 | 1,703 | -1.36% | 995 | 2 | City |
| Montague | 5 | 1,157 | 1,220 | -1.11% | 651 | 2 | City |
| Tulelake | 6 | 846 | 900 | -1.28% | 2,063 | 0 | City |
| Dorris | 7 | 807 | 856 | -1.22% | 1,150 | 1 | City |
| Fort Jones | 8 | 661 | 701 | -1.2% | 1,098 | 1 | City |
| Etna | 9 | 635 | 674 | -1.24% | 829 | 1 | City |
Yreka is the largest city in Siskiyou County, with a population of 7,656.
Etna is the smallest city in Siskiyou County, with a population of 635.
There are 9 cities in Siskiyou County, California.