10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Pell City | 1 | 14,546 | 12,991 | 2.18% | 582 | 25 | City |
| Moody | 2 | 13,839 | 13,229 | 0.89% | 564 | 24.53 | City |
| Margaret | 3 | 6,950 | 5,165 | 5.41% | 708 | 9.82 | Town |
| Odenville | 4 | 5,618 | 4,953 | 2.42% | 402 | 13.96 | City |
| Springville | 5 | 5,512 | 4,814 | 2.61% | 573 | 9.62 | City |
| Argo | 6 | 4,390 | 4,379 | 0.05% | 410 | 10.70 | Town |
| Ashville | 7 | 2,431 | 2,358 | 0.62% | 127 | 19.21 | City |
| Riverside | 8 | 2,292 | 2,227 | 0.57% | 265 | 8.66 | City |
| Ragland | 9 | 1,711 | 1,695 | 0.18% | 102 | 16.79 | Town |
| Steele | 10 | 1,005 | 992 | 0.3% | 150 | 6.71 | Town |
Pell City is the largest city in St. Clair County, with a population of 14,546.
Steele is the smallest city in St. Clair County.
There are 10 cities in St. Clair County, Alabama.