| City | County | 2026 Pop. ↓ |
|---|---|---|
| Star | Ada County | 22,547 |
| Sandpoint | Bonner County | 11,056 |
| Shelley | Bingham County | 5,412 |
| St. Anthony | Fremont County | 4,081 |
| Salmon | Lemhi County | 3,327 |
| Soda Springs | Caribou County | 3,176 |
| Sugar City | Madison County | 2,631 |
| Spirit Lake | Kootenai County | 2,516 |
| St. Maries | Benewah County | 2,485 |
| Shoshone | Lincoln County | 1,796 |
| Sun Valley | Blaine County | 1,779 |
| Smelterville | Shoshone County | 822 |
| Silverton | Shoshone County | 746 |
| Swan Valley | Bonneville County | 338 |
| St. Charles | Bear Lake County | 190 |
| Stites | Idaho County | 187 |
| Sweetwater | Nez Perce County | 174 |
| Stanley | Custer County | 125 |
| Smiths Ferry | Idaho County | 65 |
| State Line | Kootenai County | 38 |
| Spencer | Clark County | 28 |