| Zip Code | City | Population ↓ |
|---|---|---|
| 97838 | Hermiston | 28,512 |
| 97801 | Pendleton | 21,575 |
| 97862 | Milton Freewater | 12,313 |
| 97882 | Umatilla | 7,976 |
| 97875 | Stanfield | 2,410 |
| 97868 | Pilot Rock | 1,598 |
| 97813 | Athena | 1,508 |
| 97886 | Weston | 1,221 |
| 97826 | Echo | 1,178 |
| 97810 | Adams | 759 |
| 97835 | Helix | 608 |
| 97880 | Ukiah | 248 |
| 97859 | Meacham | 95 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 13 ZCTAs in Umatilla County, Oregon (US Census).