12 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 62959 | Marion | 27,793 |
| 62948 | Herrin | 12,758 |
| 62918 | Carterville | 10,658 |
| 62951 | Johnston City | 5,342 |
| 62902 | Carbondale | 4,135 |
| 62922 | Creal Springs | 2,608 |
| 62974 | Pittsburg | 1,536 |
| 62933 | Energy | 1,101 |
| 62949 | Hurst | 702 |
| 62915 | Cambria | 384 |
| 62921 | Colp | 233 |
| 62841 | Freeman Spur | 118 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 12 ZCTAs in Williamson County, Illinois (US Census).