Founded in 1841, Grundy County is one of 102 counties in the state of Illinois. Historically, Grundy County was formed from LaSalle County. The city of Morris is the county seat. With FIPS code of 63, Grundy County has a population of 52,989 and area of 418 square miles (1,083 km2).
List of all cities in Grundy County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Braceville, IL | 60407 | 815/779 |
| Carbon Hill, IL | 60416 | 815/779 |
| Coal City, IL | 60416 | 815/779 |
| Diamond, IL | 60416 | 815/779 |
| East Brooklyn, IL | 60474 | 815/779 |
| Eileen, IL | 60416 | 815/779 |
| Gardner, IL | 60424 | 815/779 |
| Godley, IL | 60407 | 815/779 |
| Kinsman, IL | 60437 | 815/779 |
| Mazon, IL | 60444 | 815/779 |
| Minooka, IL | 60447 | 815/779 |
| Morris, IL | 60450 | 815/779 |
| South Wilmington, IL | 60474 | 815/779 |
| Verona, IL | 60479 | 815/779 |