There are 27 zip codes in St. Clair County, Illinois. The most populated is 62269, located in O'Fallon. * 2024 populations estimated based on the latest ACS 5-year data.
Zip Code | Population | City |
|---|---|---|
| 62269 | 35,467 | O'Fallon |
| 62221 | 29,454 | Belleville |
| 62226 | 29,333 | Belleville |
| 62220 | 19,277 | Belleville |
| 62208 | 16,690 | Fairview Heights |
| 62223 | 16,534 | Belleville |
| 62206 | 13,477 | East Saint Louis |
| 62258 | 10,572 | Mascoutah |
| 62232 | 6,920 | Caseyville |
| 62207 | 6,637 | East Saint Louis |
| 62254 | 6,586 | Lebanon |
| 62260 | 6,461 | Millstadt |
| 62243 | 6,271 | Freeburg |
| 62203 | 6,076 | East Saint Louis |
| 62204 | 5,908 | East Saint Louis |
| 62205 | 5,754 | East Saint Louis |
| 62225 | 5,359 | Scott Air Force Base |
| 62201 | 5,166 | East Saint Louis |
| 62285 | 4,512 | Smithton |
| 62239 | 4,076 | Dupo |
| 62264 | 3,237 | New Athens |
| 62240 | 2,197 | East Carondelet |
| 62257 | 1,897 | Marissa |
| 62255 | 1,030 | Lenzburg |
| 62282 | 646 | Saint Libory |
| 62059 | 629 | Lovejoy |
| 62289 | 397 | Summerfield |