14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hamilton | 1 | 6,949 | 7,059 | 0.07% | 183 | 38 | City |
| Hamilton | 2 | 6,949 | 6,922 | 0.07% | 183 | 38 | City |
| Winfield | 3 | 4,862 | 4,849 | 0% | 273 | 18 | City |
| Winfield | 4 | 4,862 | 4,862 | 0% | 273 | 18 | City |
| Guin | 5 | 2,124 | 2,194 | -0.61% | 142 | 15 | City |
| Guin | 6 | 2,124 | 2,187 | -0.61% | 142 | 15 | City |
| Hackleburg | 7 | 1,453 | 1,430 | 0.35% | 95 | 15 | Town |
| Hackleburg | 8 | 1,453 | 1,428 | 0.35% | 95 | 15 | Town |
| Bear Creek | 9 | 1,055 | 1,038 | 0.29% | 77 | 14 | Town |
| Bear Creek | 10 | 1,055 | 1,038 | 0.29% | 77 | 14 | Town |
| Brilliant | 11 | 840 | 837 | 0.12% | 79 | 11 | Town |
| Brilliant | 12 | 840 | 835 | 0.12% | 79 | 11 | Town |
| Twin | 13 | 358 | 361 | -0.28% | 106 | 3 | Town |
| Twin | 14 | 358 | 360 | -0.28% | 106 | 3 | Town |
Hamilton is the largest city in Marion County, with a population of 6,949.
Twin is the smallest city in Marion County, with a population of 358.
There are 14 cities in Marion County, Alabama.