| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Farmington | 1 | 19,555 | 17,730 | 1.71% | 2,060 | 9 | City |
| Park Hills | 2 | 8,780 | 8,605 | 0.31% | 432 | 20 | City |
| Bonne Terre | 3 | 6,566 | 6,862 | -1.05% | 1,614 | 4 | City |
| Desloge | 4 | 4,816 | 4,823 | -0.06% | 1,650 | 3 | City |
| Bismarck | 5 | 1,221 | 1,233 | -0.25% | 1,226 | 1 | City |
| Leadwood | 6 | 1,152 | 1,175 | -0.52% | 996 | 1 | City |
| Leadington | 7 | 784 | 767 | -0.13% | 860 | 1 | City |
| Iron Mountain Lake | 8 | 647 | 641 | 0% | 330 | 2 | City |
Farmington is the largest city in St. Francois County, with a population of 19,555.
Iron Mountain Lake is the smallest city in St. Francois County, with a population of 647.
There are 8 cities in St. Francois County, Missouri.