Founded in 1826, McDonough County is one of 102 counties in the state of Illinois. Historically, McDonough County was formed from Schuyler County. The city of Macomb is the county seat. With FIPS code of 109, McDonough County has a population of 26,828 and area of 589 square miles (1,526 km2).
List of all cities in McDonough County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Adair, IL | 61411 | 309 |
| Bardolph, IL | 61416 | 309 |
| Blandinsville, IL | 61420 | 309 |
| 61475 | 309 | |
| Bushnell, IL | 61422 | 309 |
| Colchester, IL | 62326 | 309 |
| Fandon, IL | 62326 | 309 |
| Good Hope, IL | 61438 | 309 |
| Industry, IL | 61440 | 309 |
| Macomb, IL | 61455 | 309 |
| Prairie City, IL | 61470 | 309 |
| Sciota, IL | 61475 | 309 |
| Tennessee, IL | 62374 | 309 |
| Walnut Grove, IL | 61470 | 309 |