14 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Rexburg | Madison County | 40,344 |
| Rathdrum | Kootenai County | 13,107 |
| Rupert | Minidoka County | 6,470 |
| Rigby | Jefferson County | 5,913 |
| Robie Creek | Ada County | 1,256 |
| Riverside | Bingham County | 1,133 |
| Ririe | Jefferson County | 731 |
| Roberts | Jefferson County | 630 |
| Richfield | Lincoln County | 493 |
| Riggins | Idaho County | 419 |
| Rockford Bay | Kootenai County | 337 |
| Rockland | Power County | 270 |
| Rockford | Bingham County | 180 |
| Reubens | Lewis County | 46 |