22 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 17801 | Sunbury | 16,429 |
| 17847 | Milton | 11,260 |
| 17866 | Coal Township | 9,769 |
| 17872 | Shamokin | 8,894 |
| 17857 | Northumberland | 7,671 |
| 17851 | Mount Carmel | 7,234 |
| 17777 | Watsontown | 7,030 |
| 17834 | Kulpmont | 3,480 |
| 17860 | Paxinos | 2,332 |
| 17830 | Herndon | 1,938 |
| 17017 | Dalmatia | 1,509 |
| 17881 | Trevorton | 1,479 |
| 17823 | Dornsife | 1,258 |
| 17868 | Riverside | 719 |
| 17832 | Marion Heights | 578 |
| 17850 | Montandon | 576 |
| 17867 | Rebuck | 239 |
| 17749 | McEwensville | 234 |
| 17836 | Leck Kill | 190 |
| 17840 | Locust Gap | 188 |
| 17865 | Potts Grove | 24 |
| 17730 | Dewart | 11 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 22 ZCTAs in Northumberland County, Pennsylvania (US Census).