9 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Orem | Utah County | 95,755 |
| Ogden | Weber County | 89,334 |
| Oakley | Summit County | 1,551 |
| Orangeville | Emery County | 1,286 |
| Oljato-Monument Valley | Apache County | 685 |
| Oak City | Millard County | 643 |
| Orderville | Kane County | 586 |
| Oasis | Millard County | 71 |
| Ophir | Tooele County | 32 |