Founded in 1831, Effingham County is one of 102 counties in the state of Illinois. Historically, Effingham County was formed from Fayette and Crawford County. The city of Effingham is the county seat. With FIPS code of 49, Effingham County has a population of 34,430 and area of 478 square miles (1,238 km2).
List of all cities in Effingham County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Altamont, IL | 62411 | 618/730 |
| Beecher City, IL | 62414 | 618/730 |
| Blue Point, IL | 62401 | 217 |
| Boggsville, IL | 62401 | 217 |
| Dieterich, IL | 62424 | 217 |
| Douglas, IL | 62401 | 217 |
| Edgewood, IL | 62426 | 618/730 |
| Effingham, IL | 62401 | 217 |
| Funkhouser, IL | 62401 | 217 |
| Gila, IL | 62445 | 217 |
| Gilmore, IL | 62443 | 618/730 |
| Green Creek, IL | 62401 | 217 |
| Heartville, IL | 62401 | 217 |
| Island Grove, IL | 62467 | 217 |
| Laclede, IL | 62426 | 618/730 |
| Lake Sara, IL | 62401 | 217 |
| Larkinsburg, IL | 62426 | 618/730 |
| Lillyville, IL | 62401 | 217 |
| Mason, IL | 62443 | 618/730 |
| Montrose, IL | 62445 | 217 |
| Northmore Heights, IL | 62401 | 217 |
| Park Hills, IL | 62401 | 217 |
| Saint Francis, IL | 62467 | 217 |
| Saint Marys, IL | 62401 | 217 |
| Shumway, IL | 62461 | 217 |
| Teutopolis, IL | 62467 | 217 |
| Watson, IL | 62473 | 217 |
| Woodbury, IL | 62445 | 217 |
| Wrights Corner, IL | 62414 | 618/730 |