Founded in 1833, Iroquois County is one of 102 counties in the state of Illinois. Historically, Iroquois County was formed from Vermilion County. The city of Watseka is the county seat. With FIPS code of 75, Iroquois County has a population of 26,827 and area of 1,117 square miles (2,893 km2).
List of all cities in Iroquois County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Ashkum, IL | 60911 | 815/779 |
| Beaverville, IL | 60912 | 815/779 |
| Buckley, IL | 60918 | 217 |
| Chebanse, IL | 60922 | 815/779 |
| Cissna Park, IL | 60924 | 815/779 |
| Claytonville, IL | 60926 | 815/779 |
| Clifton, IL | 60927 | 815/779 |
| Crescent City, IL | 60928 | 815/779 |
| Danforth, IL | 60930 | 815/779 |
| Donovan, IL | 60931 | 815/779 |
| Gilman, IL | 60938 | 815/779 |
| Goodwine, IL | 60939 | 815/779 |
| Iroquois, IL | 60945 | 815/779 |
| Loda, IL | 60948 | 217 |
| Martinton, IL | 60951 | 815/779 |
| Milford, IL | 60953 | 815/779 |
| Onarga, IL | 60955 | 815/779 |
| Papineau, IL | 60956 | 815/779 |
| Sheldon, IL | 60966 | 815/779 |
| Stockland, IL | 60967 | 815/779 |
| Thawville, IL | 60968 | 217 |
| Watseka, IL | 60970 | 815/779 |
| Wellington, IL | 60973 | 815/779 |
| Woodland, IL | 60974 | 815/779 |