9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Webster City | 1 | 7,749 | 7,816 | -0.18% | 842 | 9 | City |
| Jewell Junction | 2 | 1,239 | 1,211 | 0.41% | 320 | 4 | City |
| Stratford | 3 | 684 | 702 | -0.58% | 377 | 2 | City |
| Ellsworth | 4 | 492 | 506 | -0.61% | 557 | 1 | City |
| Stanhope | 5 | 352 | 362 | -0.56% | 359 | 1 | City |
| Williams | 6 | 297 | 306 | -0.67% | 350 | 1 | City |
| Kamrar | 7 | 177 | 182 | -0.56% | 207 | 1 | City |
| Blairsburg | 8 | 175 | 174 | 0% | 273 | 1 | City |
| Randall | 9 | 156 | 155 | 0% | 385 | 0 | City |
Webster City is the largest city in Hamilton County, with a population of 7,749.
Randall is the smallest city in Hamilton County, with a population of 156.
There are 9 cities in Hamilton County, Iowa.