12 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iowa Falls | 1 | 4,944 | 5,090 | -0.48% | 873 | 6 | City |
| Eldora | 2 | 2,567 | 2,650 | -0.54% | 600 | 4 | City |
| Ackley | 3 | 1,510 | 1,594 | -0.92% | 615 | 2 | City |
| Hubbard | 4 | 826 | 859 | -0.6% | 465 | 2 | City |
| Alden | 5 | 726 | 761 | -0.82% | 471 | 2 | City |
| Radcliffe | 6 | 533 | 554 | -0.56% | 535 | 1 | City |
| Union | 7 | 371 | 391 | -0.8% | 650 | 1 | City |
| McCallsburg | 8 | 359 | 350 | 0.56% | 787 | 0 | City |
| Steamboat Rock | 9 | 259 | 265 | -0.38% | 480 | 1 | City |
| New Providence | 10 | 231 | 236 | -0.43% | 231 | 1 | City |
| Whitten | 11 | 97 | 100 | 0% | 195 | 0 | City |
| Buckeye | 12 | 81 | 84 | 0% | 82 | 1 | City |
Iowa Falls is the largest city in Hardin County, with a population of 4,944.
Buckeye is the smallest city in Hardin County, with a population of 81.
There are 12 cities in Hardin County, Iowa.