| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sidney | 1 | 1,046 | 1,067 | -0.48% | 763 | 1 | City |
| Tabor | 2 | 979 | 1,007 | -0.61% | 758 | 1 | City |
| Hamburg | 3 | 860 | 881 | -0.69% | 574 | 1 | City |
| Farragut | 4 | 479 | 487 | -0.42% | 1,195 | 0 | City |
| Riverton | 5 | 241 | 248 | -0.82% | 400 | 1 | City |
| Randolph | 6 | 185 | 189 | -0.54% | 617 | 0 | City |
| Thurman | 7 | 162 | 163 | -0.61% | 287 | 1 | City |
| Imogene | 8 | 36 | 38 | -2.7% | 73 | 0 | City |
Sidney is the largest city in Fremont County, with a population of 1,046.
Imogene is the smallest city in Fremont County, with a population of 36.
There are 8 cities in Fremont County, Iowa.