| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fort Payne | 1 | 15,249 | 14,856 | 0.4% | 270 | 56 | City |
| Rainsville | 2 | 6,131 | 5,531 | 1.84% | 296 | 21 | City |
| Henagar | 3 | 2,372 | 2,304 | 0.47% | 105 | 23 | City |
| Collinsville | 4 | 2,127 | 2,066 | 0.28% | 636 | 3 | Town |
| Sylvania | 5 | 1,863 | 1,799 | 0.54% | 219 | 9 | Town |
| Crossville | 6 | 1,852 | 1,829 | 0.05% | 221 | 8 | Town |
| Sardis City | 7 | 1,779 | 1,818 | -0.45% | 226 | 8 | Town |
| Fyffe | 8 | 988 | 975 | 0.2% | 199 | 5 | Town |
| Powell | 9 | 953 | 910 | 0.74% | 198 | 5 | Town |
| Geraldine | 10 | 919 | 909 | 0.11% | 240 | 4 | Town |
| Ider | 11 | 745 | 726 | 0.4% | 137 | 5 | Town |
| Valley Head | 12 | 600 | 578 | 0.5% | 159 | 4 | Town |
| Hammondville | 13 | 432 | 423 | 0.23% | 89 | 5 | Town |
| Mentone | 14 | 340 | 323 | 0.89% | 79 | 4 | Town |
| Shiloh | 15 | 334 | 327 | 0% | 157 | 2 | Town |
| Pine Ridge | 16 | 271 | 260 | 0.37% | 203 | 1 | Town |
| Lakeview | 17 | 167 | 162 | 0% | 258 | 1 | Town |
| Ridgeville | 18 | 82 | 84 | -1.2% | 100 | 1 | Town |
Fort Payne is the largest city in DeKalb County, with a population of 15,249.
Ridgeville is the smallest city in DeKalb County, with a population of 82.
There are 18 cities in DeKalb County, Alabama.