11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hampton | 1 | 4,234 | 4,329 | -0.45% | 957 | 4.42 | City |
| Sheffield | 2 | 1,095 | 1,124 | -0.54% | 197 | 5.57 | City |
| Latimer | 3 | 467 | 477 | -0.43% | 194 | 2.40 | City |
| Bradford | 4 | 303 | 61 | 7.45% | 326 | 0.93 | CDP |
| Coulter | 5 | 215 | 219 | -0.46% | 87 | 2.47 | City |
| Chapin | 6 | 171 | 162 | 6.88% | 1,727 | 0.10 | CDP |
| Alexander | 7 | 160 | 167 | -0.62% | 37 | 4.27 | City |
| Geneva | 8 | 134 | 136 | 0% | 328 | 0.41 | City |
| Hansell | 9 | 81 | 83 | 0% | 360 | 0.23 | City |
| Popejoy | 10 | 76 | 78 | 0% | 101 | 0.75 | City |
| Owasa | 11 | 29 | 31 | 0% | 52 | 0.56 | City |
Hampton is the largest city in Franklin County, with a population of 4,234.
Owasa is the smallest city in Franklin County.
There are 11 cities in Franklin County, Iowa.