3 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rosiclare | 1 | 939 | 978 | -0.84% | 484 | 1.94 | City |
| Cave-In-Rock | 2 | 219 | 229 | -0.9% | 586 | 0.37 | Village |
| Elizabethtown | 3 | 216 | 223 | -0.46% | 306 | 0.70 | Village |
Rosiclare is the largest city in Hardin County, with a population of 939.
Elizabethtown is the smallest city in Hardin County.
There are 3 cities in Hardin County, Illinois.