| Zip Code | City | Population ↓ |
|---|---|---|
| 97845 | John Day | 2,300 |
| 97820 | Canyon City | 1,137 |
| 97865 | Mount Vernon | 1,133 |
| 97869 | Prairie City | 938 |
| 97856 | Long Creek | 498 |
| 97825 | Dayville | 407 |
| 97877 | Sumpter | 319 |
| 97864 | Monument | 295 |
| 97848 | Kimberly | 215 |
| 97873 | Seneca | 167 |
| 97817 | Bates | 37 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 11 ZCTAs in Grant County, Oregon (US Census).