17 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Savanna township | 1 | 3,310 | 3,405 | -0.51% | 248 | 13.35 | Township |
| York township | 2 | 2,750 | 2,771 | -0.11% | 58 | 47.47 | Township |
| Savanna | 3 | 2,670 | 2,774 | -0.78% | 1,021 | 2.62 | City |
| Rock Creek-Lima township | 4 | 1,928 | 1,980 | -0.41% | 36 | 54.05 | Township |
| Mount Carroll township | 5 | 1,900 | 1,959 | -0.58% | 50 | 37.75 | Township |
| Thomson | 6 | 1,594 | 1,611 | -0.19% | 718 | 2.22 | Village |
| Cherry Grove-Shannon township | 7 | 1,580 | 1,541 | -0.25% | 29 | 53.61 | Township |
| Lanark | 8 | 1,444 | 1,498 | -0.76% | 1,288 | 1.12 | City |
| Mount Carroll | 9 | 1,418 | 1,475 | -0.77% | 708 | 2 | City |
| Wysox township | 10 | 1,297 | 1,335 | -0.54% | 34 | 38.08 | Township |
| Milledgeville | 11 | 988 | 1,023 | -0.7% | 1,432 | 0.69 | Village |
| Lake Carroll | 12 | 947 | 500 | 7.13% | 70 | 13.55 | CDP |
| Shannon | 13 | 880 | 800 | 1.85% | 1,826 | 0.48 | Village |
| Freedom township | 14 | 773 | 780 | -0.13% | 22 | 35.82 | Township |
| Fairhaven township | 15 | 759 | 767 | -0.13% | 20 | 38.21 | Township |
| Chadwick | 16 | 473 | 482 | -0.42% | 1,521 | 0.31 | Village |
| Elkhorn Grove township | 17 | 189 | 189 | 0.53% | 10 | 19.53 | Township |
Savanna township is the largest city in Carroll County, with a population of 3,310.
Elkhorn Grove township is the smallest city in Carroll County.
There are 17 cities in Carroll County, Illinois.