10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Pell City | 1 | 14,374 | 12,973 | 1.99% | 575 | 25 | City |
| Moody | 2 | 13,688 | 13,226 | 0.68% | 558 | 25 | City |
| Margaret | 3 | 7,019 | 5,192 | 5.49% | 715 | 10 | Town |
| Odenville | 4 | 5,899 | 4,959 | 3.29% | 422 | 14 | City |
| Springville | 5 | 5,539 | 4,803 | 2.73% | 576 | 10 | City |
| Argo | 6 | 4,362 | 4,395 | -0.16% | 408 | 11 | Town |
| Ashville | 7 | 2,414 | 2,354 | 0.5% | 126 | 19 | City |
| Riverside | 8 | 2,324 | 2,224 | 0.87% | 268 | 9 | City |
| Ragland | 9 | 1,713 | 1,690 | 0.23% | 102 | 17 | Town |
| Steele | 10 | 1,005 | 992 | 0.2% | 150 | 7 | Town |
Pell City is the largest city in St. Clair County, with a population of 14,374.
Steele is the smallest city in St. Clair County, with a population of 1,005.
There are 10 cities in St. Clair County, Alabama.