18 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fort Payne | 1 | 15,090 | 14,871 | 0.25% | 268 | 56 | City |
| Rainsville | 2 | 6,132 | 5,529 | 1.67% | 296 | 21 | City |
| Henagar | 3 | 2,330 | 2,305 | 0.17% | 103 | 23 | City |
| Collinsville | 4 | 2,063 | 2,066 | 0% | 617 | 3 | Town |
| Sylvania | 5 | 1,836 | 1,799 | 0.33% | 216 | 9 | Town |
| Crossville | 6 | 1,829 | 1,828 | 0% | 219 | 8 | Town |
| Sardis City | 7 | 1,763 | 1,820 | -0.51% | 224 | 8 | Town |
| Fyffe | 8 | 977 | 973 | 0.1% | 197 | 5 | Town |
| Powell | 9 | 939 | 909 | 0.54% | 196 | 5 | Town |
| Geraldine | 10 | 911 | 910 | 0% | 238 | 4 | Town |
| Ider | 11 | 743 | 728 | 0.41% | 137 | 5 | Town |
| Valley Head | 12 | 602 | 581 | 0.67% | 159 | 4 | Town |
| Hammondville | 13 | 430 | 423 | 0.23% | 89 | 5 | Town |
| Mentone | 14 | 339 | 323 | 0.89% | 79 | 4 | Town |
| Shiloh | 15 | 333 | 327 | 0.3% | 156 | 2 | Town |
| Pine Ridge | 16 | 271 | 262 | 0.74% | 203 | 1 | Town |
| Lakeview | 17 | 167 | 164 | 0.6% | 258 | 1 | Town |
| Ridgeville | 18 | 84 | 86 | 0% | 102 | 1 | Town |
Fort Payne is the largest city in DeKalb County, with a population of 15,090.
Ridgeville is the smallest city in DeKalb County, with a population of 84.
There are 18 cities in DeKalb County, Alabama.