Founded in 1839, Hardin County is one of 102 counties in the state of Illinois. Historically, Hardin County was formed from Pope County. The city of Elizabethtown is the county seat. With FIPS code of 69, Hardin County has a population of 3,650 and area of 177 square miles (458 km2).
List of all cities in Hardin County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Cave in Rock, IL | 62919 | 618/730 |
| Elizabethtown, IL | 62931 | 618/730 |
| Karbers Ridge, IL | 62955 | 618/730 |
| Lamb, IL | 62919 | 618/730 |
| Rock Creek, IL | 62919 | 618/730 |
| Rosiclare, IL | 62982 | 618/730 |