14 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Rexburg | Madison County | 40,927 |
| Rathdrum | Kootenai County | 13,459 |
| Rupert | Minidoka County | 6,413 |
| Rigby | Jefferson County | 5,835 |
| Robie Creek | Ada County | 1,256 |
| Riverside | Bingham County | 1,133 |
| Ririe | Jefferson County | 727 |
| Roberts | Jefferson County | 603 |
| Richfield | Lincoln County | 488 |
| Riggins | Idaho County | 400 |
| Rockford Bay | Kootenai County | 337 |
| Rockland | Power County | 268 |
| Rockford | Bingham County | 180 |
| Reubens | Lewis County | 49 |