| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| St. Anthony | 1 | 4,081 | 3,691 | 2.28% | 2,120 | 2 | City |
| Ashton | 2 | 977 | 984 | 0% | 1,531 | 1 | City |
| Teton | 3 | 846 | 790 | 1.81% | 1,228 | 1 | City |
| Newdale | 4 | 328 | 331 | -0.3% | 1,783 | 0 | City |
| Parker | 5 | 288 | 294 | -0.35% | 830 | 0 | City |
| Island Park | 6 | 189 | 193 | -0.53% | 31 | 6 | City |
| Drummond | 7 | 15 | 14 | 0% | 156 | 0 | City |
| Warm River | 8 | 1 | 1 | 0% | 2.0 | 1 | City |
St. Anthony is the largest city in Fremont County, with a population of 4,081.
Warm River is the smallest city in Fremont County, with a population of 1.
There are 8 cities in Fremont County, Idaho.