Post Offices List in Effingham County, Illinois:
| Altamont Post Office | 122 W Washington Ave, Altamont, IL 62411 |
| Dieterich Post Office | 201 S Main St, Dieterich, IL 62424 |
| Edgewood Post Office | 807 Broad St, Edgewood, IL 62426 |
| Effingham Post Office | 210 N 3rd St, Effingham, IL 62401 |
| Mason Post Office | 755 Adams St, Mason, IL 62443 |
| Shumway Post Office | 101 E Main St, Shumway, IL 62461 |
| Teutopolis Post Office | 100 W Main St, Teutopolis, IL 62467 |
| Watson Post Office | 101 S Monroe St, Watson, IL 62473 |