| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kewanee | 1 | 12,036 | 12,464 | -0.65% | 1,824 | 7 | City |
| Geneseo | 2 | 6,495 | 6,536 | -0.15% | 1,379 | 5 | City |
| Colona | 3 | 4,919 | 5,025 | -0.38% | 1,288 | 4 | City |
| Galva | 4 | 2,366 | 2,457 | -0.71% | 856 | 3 | City |
| Cambridge | 5 | 2,006 | 2,078 | -0.69% | 1,008 | 2 | Village |
| Orion | 6 | 1,698 | 1,752 | -0.59% | 1,816 | 1 | Village |
| Atkinson | 7 | 917 | 953 | -0.76% | 481 | 2 | Town |
| Annawan | 8 | 852 | 884 | -0.7% | 398 | 2 | Town |
| Woodhull | 9 | 726 | 753 | -0.68% | 827 | 1 | Village |
| Alpha | 10 | 648 | 671 | -0.77% | 2,084 | 0 | Village |
| Andover | 11 | 532 | 553 | -0.75% | 537 | 1 | Village |
| Hooppole | 12 | 171 | 180 | -1.16% | 460 | 0 | Village |
| Cleveland | 13 | 157 | 163 | -1.26% | 534 | 0 | Village |
| Bishop Hill | 14 | 111 | 113 | -0.89% | 208 | 1 | Village |
Kewanee is the largest city in Henry County, with a population of 12,036.
Bishop Hill is the smallest city in Henry County, with a population of 111.
There are 14 cities in Henry County, Illinois.