13 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iowa Falls | 1 | 4,945 | 5,087 | -0.56% | 918 | 5.39 | City |
| Eldora | 2 | 2,547 | 2,651 | -0.82% | 595 | 4.28 | City |
| Ackley | 3 | 1,500 | 1,595 | -1.25% | 611 | 2.46 | City |
| Hubbard | 4 | 822 | 859 | -0.84% | 463 | 1.77 | City |
| Alden | 5 | 722 | 761 | -1.1% | 469 | 1.54 | City |
| Radcliffe | 6 | 530 | 555 | -0.94% | 532 | 1 | City |
| Union | 7 | 373 | 393 | -1.06% | 653 | 0.57 | City |
| McCallsburg | 8 | 356 | 351 | 0.28% | 781 | 0.46 | City |
| Steamboat Rock | 9 | 258 | 265 | -0.39% | 478 | 0.54 | City |
| New Providence | 10 | 226 | 235 | -0.88% | 226 | 1 | City |
| Garden City | 11 | 159 | 150 | 7.43% | 159 | 1 | CDP |
| Whitten | 12 | 96 | 101 | -1.03% | 193 | 0.50 | City |
| Buckeye | 13 | 80 | 84 | -1.23% | 81 | 0.99 | City |
Iowa Falls is the largest city in Hardin County, with a population of 4,945.
Buckeye is the smallest city in Hardin County.
There are 13 cities in Hardin County, Iowa.