| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Savanna | 1 | 2,678 | 2,800 | -0.78% | 1,024 | 3 | City |
| Thomson | 2 | 1,604 | 1,612 | -0.12% | 723 | 2 | Village |
| Lanark | 3 | 1,440 | 1,507 | -0.83% | 1,285 | 1 | City |
| Mount Carroll | 4 | 1,421 | 1,487 | -0.77% | 709 | 2 | City |
| Milledgeville | 5 | 980 | 1,025 | -0.81% | 1,420 | 1 | Village |
| Shannon | 6 | 845 | 796 | 1.2% | 1,753 | 0 | Village |
| Chadwick | 7 | 474 | 482 | -0.42% | 1,524 | 0 | Village |
Savanna is the largest city in Carroll County, with a population of 2,678.
Chadwick is the smallest city in Carroll County, with a population of 474.
There are 7 cities in Carroll County, Illinois.