| City | County | 2026 Pop. ↓ |
|---|---|---|
| Rexburg | Madison County | 40,465 |
| Rathdrum | Kootenai County | 14,058 |
| Rupert | Minidoka County | 6,531 |
| Rigby | Jefferson County | 5,909 |
| Robie Creek | Ada County | 1,258 |
| Riverside | Bingham County | 1,192 |
| Ririe | Jefferson County | 722 |
| Roberts | Jefferson County | 592 |
| Richfield | Lincoln County | 497 |
| Riggins | Idaho County | 402 |
| Rockford Bay | Kootenai County | 337 |
| Rockford | Bingham County | 312 |
| Rockland | Power County | 262 |
| Reubens | Lewis County | 53 |