41 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fort Payne | 1 | 15,053 | 14,868 | 0.24% | 267 | 56 | City |
| Fort Payne | 2 | 15,053 | 14,871 | 0.24% | 267 | 56 | City |
| Rainsville | 3 | 6,031 | 5,515 | 1.69% | 291 | 21 | City |
| Rainsville | 4 | 6,031 | 5,529 | 1.69% | 291 | 21 | City |
| Henagar | 5 | 2,326 | 2,304 | 0.17% | 103 | 23 | City |
| Henagar | 6 | 2,326 | 2,305 | 0.17% | 103 | 23 | City |
| Carlisle-Rockledge | 7 | 2,256 | 2,530 | 0.36% | 139 | 16 | CDP |
| Whitesboro | 8 | 2,133 | 2,161 | 0% | 122 | 17 | CDP |
| Collinsville | 9 | 2,063 | 2,067 | -0.05% | 617 | 3 | Town |
| Collinsville | 10 | 2,063 | 2,066 | -0.05% | 617 | 3 | Town |
| Sylvania | 11 | 1,830 | 1,797 | 0.33% | 215 | 9 | Town |
| Sylvania | 12 | 1,830 | 1,799 | 0.33% | 215 | 9 | Town |
| Crossville | 13 | 1,829 | 1,829 | 0% | 219 | 8 | Town |
| Crossville | 14 | 1,829 | 1,828 | 0% | 219 | 8 | Town |
| Sardis City | 15 | 1,772 | 1,819 | -0.56% | 225 | 8 | Town |
| Sardis City | 16 | 1,772 | 1,820 | -0.56% | 225 | 8 | Town |
| Fyffe | 17 | 976 | 973 | 0% | 196 | 5 | Town |
| Fyffe | 18 | 976 | 973 | 0% | 196 | 5 | Town |
| Powell | 19 | 934 | 909 | 0.54% | 195 | 5 | Town |
| Powell | 20 | 934 | 909 | 0.54% | 195 | 5 | Town |
| Geraldine | 21 | 911 | 910 | 0% | 238 | 4 | Town |
| Geraldine | 22 | 911 | 910 | 0% | 238 | 4 | Town |
| New Union | 23 | 775 | 1,008 | -1.52% | 63 | 12 | CDP |
| Ider | 24 | 740 | 726 | 0.27% | 136 | 5 | Town |
| Ider | 25 | 740 | 728 | 0.27% | 136 | 5 | Town |
| Ivalee | 26 | 640 | 733 | -2.44% | 86 | 7 | CDP |
| Valley Head | 27 | 598 | 581 | 0.5% | 158 | 4 | Town |
| Valley Head | 28 | 598 | 581 | 0.5% | 158 | 4 | Town |
| Hammondville | 29 | 429 | 423 | 0.23% | 88 | 5 | Town |
| Hammondville | 30 | 429 | 423 | 0.23% | 88 | 5 | Town |
| Mentone | 31 | 336 | 323 | 0.6% | 78 | 4 | Town |
| Mentone | 32 | 336 | 323 | 0.6% | 78 | 4 | Town |
| Shiloh | 33 | 332 | 327 | 0.3% | 156 | 2 | Town |
| Shiloh | 34 | 332 | 327 | 0.3% | 156 | 2 | Town |
| Pine Ridge | 35 | 269 | 262 | 0.37% | 202 | 1 | Town |
| Pine Ridge | 36 | 269 | 262 | 0.37% | 202 | 1 | Town |
| Lakeview | 37 | 166 | 164 | 0% | 256 | 1 | Town |
| Lakeview | 38 | 166 | 164 | 0% | 256 | 1 | Town |
| Bristow Cove | 39 | 103 | 465 | -27.46% | 9 | 11 | CDP |
| Ridgeville | 40 | 84 | 86 | -1.18% | 102 | 1 | Town |
| Ridgeville | 41 | 84 | 86 | -1.18% | 102 | 1 | Town |
Fort Payne is the largest city in DeKalb County, with a population of 15,053.
Ridgeville is the smallest city in DeKalb County, with a population of 84.
There are 41 cities in DeKalb County, Alabama.