14 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Rexburg | Madison County | 41,160 |
| Rathdrum | Kootenai County | 14,293 |
| Rupert | Minidoka County | 6,483 |
| Rigby | Jefferson County | 5,988 |
| Robie Creek | Ada County | 1,258 |
| Riverside | Bingham County | 1,192 |
| Ririe | Jefferson County | 739 |
| Roberts | Jefferson County | 624 |
| Richfield | Lincoln County | 500 |
| Riggins | Idaho County | 407 |
| Rockford Bay | Kootenai County | 337 |
| Rockford | Bingham County | 312 |
| Rockland | Power County | 274 |
| Reubens | Lewis County | 50 |