| Zip Code | City | Population ↓ |
|---|---|---|
| 62959 | Marion | 27,255 |
| 62948 | Herrin | 12,679 |
| 62918 | Carterville | 10,844 |
| 62951 | Johnston City | 5,574 |
| 62902 | Carbondale | 4,344 |
| 62922 | Creal Springs | 2,824 |
| 62974 | Pittsburg | 1,523 |
| 62933 | Energy | 1,253 |
| 62949 | Hurst | 770 |
| 62915 | Cambria | 431 |
| 62921 | Colp | 243 |
| 62841 | Freeman Spur | 140 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 12 ZCTAs in Williamson County, Illinois (US Census).