22 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 17801 | Sunbury | 16,229 |
| 17847 | Milton | 11,461 |
| 17866 | Coal Township | 9,808 |
| 17872 | Shamokin | 8,950 |
| 17857 | Northumberland | 7,682 |
| 17851 | Mount Carmel | 7,174 |
| 17777 | Watsontown | 6,801 |
| 17834 | Kulpmont | 3,525 |
| 17860 | Paxinos | 2,605 |
| 17830 | Herndon | 1,932 |
| 17017 | Dalmatia | 1,572 |
| 17881 | Trevorton | 1,510 |
| 17823 | Dornsife | 1,316 |
| 17868 | Riverside | 744 |
| 17832 | Marion Heights | 694 |
| 17850 | Montandon | 618 |
| 17836 | Leck Kill | 249 |
| 17749 | McEwensville | 218 |
| 17840 | Locust Gap | 197 |
| 17867 | Rebuck | 190 |
| 17730 | Dewart | 38 |
| 17865 | Potts Grove | 15 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 22 ZCTAs in Northumberland County, Pennsylvania (US Census).