14 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kewanee | 1 | 11,985 | 12,468 | -0.66% | 1,816 | 7 | City |
| Geneseo | 2 | 6,483 | 6,543 | -0.15% | 1,376 | 5 | City |
| Colona | 3 | 4,921 | 5,037 | -0.38% | 1,289 | 4 | City |
| Galva | 4 | 2,364 | 2,459 | -0.67% | 855 | 3 | City |
| Cambridge | 5 | 2,009 | 2,084 | -0.59% | 1,009 | 2 | Village |
| Orion | 6 | 1,694 | 1,753 | -0.59% | 1,812 | 1 | Village |
| Atkinson | 7 | 917 | 955 | -0.65% | 481 | 2 | Town |
| Annawan | 8 | 848 | 884 | -0.7% | 396 | 2 | Town |
| Woodhull | 9 | 723 | 753 | -0.69% | 823 | 1 | Village |
| Alpha | 10 | 644 | 670 | -0.62% | 2,071 | 0 | Village |
| Andover | 11 | 531 | 555 | -0.75% | 536 | 1 | Village |
| Hooppole | 12 | 170 | 179 | -0.58% | 457 | 0 | Village |
| Cleveland | 13 | 150 | 159 | -0.66% | 510 | 0 | Village |
| Bishop Hill | 14 | 111 | 113 | 0% | 208 | 1 | Village |
Kewanee is the largest city in Henry County, with a population of 11,985.
Bishop Hill is the smallest city in Henry County, with a population of 111.
There are 14 cities in Henry County, Illinois.