11 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 17837 | Lewisburg | 18,403 |
| 17844 | Mifflinburg | 10,291 |
| 17856 | New Columbia | 3,167 |
| 17845 | Millmont | 2,058 |
| 17855 | New Berlin | 1,014 |
| 17886 | West Milton | 804 |
| 17887 | White Deer | 591 |
| 17829 | Hartleton | 212 |
| 17885 | Weikert | 181 |
| 17835 | Laurelton | 114 |
| 17880 | Swengel | 29 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 11 ZCTAs in Union County, Pennsylvania (US Census).