Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Yreka | 1 | 7,812 | 7,795 | 0.05% | 783 | 10.0 | City |
| Lake Shastina | 2 | 3,509 | 2,790 | 7.67% | 874 | 4.0 | CDP |
| Mount Shasta | 3 | 3,165 | 3,219 | -0.44% | 840 | 3.8 | City |
| Weed | 4 | 2,480 | 2,856 | -3.65% | 515 | 4.8 | City |
| Dunsmuir | 5 | 1,622 | 1,702 | -1.22% | 1,011 | 1.6 | City |
| Montague | 6 | 1,169 | 1,221 | -1.1% | 657 | 1.8 | City |
| McCloud | 7 | 935 | 899 | -1.27% | 386 | 2.4 | CDP |
| Tulelake | 8 | 856 | 900 | -1.27% | 2,088 | 0.4 | City |
| Dorris | 9 | 822 | 861 | -1.2% | 1,171 | 0.7 | City |
| Fort Jones | 10 | 665 | 697 | -1.19% | 1,105 | 0.6 | City |
| Etna | 11 | 645 | 676 | -1.23% | 842 | 0.8 | City |
| Happy Camp | 12 | 594 | 861 | -6.6% | 49 | 12.1 | CDP |
| Hornbrook | 13 | 403 | 243 | 2.81% | 345 | 1.2 | CDP |
| Grenada | 14 | 207 | 295 | -5.48% | 400 | 0.5 | CDP |
| Macdoel | 15 | 145 | 26 | 0.69% | 868 | 0.2 | CDP |
| Gazelle | 16 | 144 | 111 | 8.27% | 214 | 0.7 | CDP |
| Mount Hebron | 17 | 132 | 61 | 8.2% | 176 | 0.8 | CDP |
| Tennant | 18 | 93 | 21 | 6.9% | 274 | 0.3 | CDP |
| Greenview | 19 | 76 | 139 | -10.59% | 59 | 1.3 | CDP |
| Edgewood | 20 | 54 | 39 | 8% | 53 | 1.0 | CDP |
| Carrick | 21 | 49 | 58 | -10.91% | 831 | 0.1 | CDP |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Yreka is the largest city in Siskiyou County.
Carrick is the smallest city in Siskiyou County.
There are 21 cities in Siskiyou County, California.