43 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kewanee | 1 | 12,065 | 12,468 | -0.67% | 1,829 | 7 | City |
| Kewanee | 2 | 9,459 | 9,765 | -0.53% | 262 | 36 | Township |
| Geneseo | 3 | 7,484 | 7,554 | -0.2% | 206 | 36 | Township |
| Colona | 4 | 6,575 | 6,698 | -0.18% | 227 | 29 | Township |
| Geneseo | 5 | 6,493 | 6,543 | -0.15% | 1,378 | 5 | City |
| Colona | 6 | 4,940 | 5,037 | -0.4% | 1,294 | 4 | City |
| Wethersfield | 7 | 3,689 | 3,797 | -0.46% | 104 | 36 | Township |
| Western | 8 | 2,850 | 2,926 | -0.42% | 80 | 35 | Township |
| Galva | 9 | 2,630 | 2,708 | -0.42% | 77 | 34 | Township |
| Galva | 10 | 2,380 | 2,459 | -0.67% | 861 | 3 | City |
| Cambridge | 11 | 2,356 | 2,423 | -0.46% | 64 | 37 | Township |
| Hanna | 12 | 2,332 | 2,391 | -0.43% | 122 | 19 | Township |
| Cambridge | 13 | 2,021 | 2,084 | -0.64% | 1,015 | 2 | Village |
| Orion | 14 | 1,704 | 1,753 | -0.58% | 1,822 | 1 | Village |
| Phenix | 15 | 1,651 | 1,691 | -0.3% | 50 | 33 | Township |
| Atkinson | 16 | 1,196 | 1,236 | -0.66% | 34 | 35 | Township |
| Oxford | 17 | 1,121 | 1,154 | -0.44% | 31 | 36 | Township |
| Orion | 18 | 1,114 | 1,144 | -0.27% | 31 | 36 | Township |
| Annawan | 19 | 1,082 | 1,118 | -0.55% | 30 | 36 | Township |
| Atkinson | 20 | 923 | 955 | -0.75% | 484 | 2 | Town |
| Andover | 21 | 863 | 888 | -0.35% | 24 | 37 | Township |
| Annawan | 22 | 854 | 884 | -0.7% | 399 | 2 | Town |
| Clover | 23 | 822 | 848 | -0.48% | 24 | 35 | Township |
| Lynn | 24 | 767 | 788 | -0.39% | 21 | 36 | Township |
| Woodhull | 25 | 728 | 753 | -0.68% | 829 | 1 | Village |
| Alpha | 26 | 648 | 670 | -0.77% | 2,084 | 0 | Village |
| Edford | 27 | 638 | 652 | -0.31% | 23 | 27 | Township |
| Andover | 28 | 535 | 555 | -0.74% | 540 | 1 | Village |
| Yorktown | 29 | 426 | 438 | -0.23% | 12 | 36 | Township |
| Osco | 30 | 413 | 426 | -0.48% | 11 | 36 | Township |
| Weller | 31 | 389 | 396 | -0.26% | 11 | 34 | Township |
| Munson | 32 | 348 | 358 | -0.85% | 10 | 36 | Township |
| Cornwall | 33 | 252 | 258 | -0.4% | 7 | 36 | Township |
| Ophiem | 34 | 238 | 180 | 7.21% | 201 | 1 | CDP |
| Burns | 35 | 233 | 238 | -0.43% | 6 | 36 | Township |
| Hooppole | 36 | 171 | 179 | -1.16% | 460 | 0 | Village |
| Alba | 37 | 166 | 171 | -0.6% | 5 | 36 | Township |
| Cleveland | 38 | 151 | 159 | -1.31% | 514 | 0 | Village |
| Osco | 39 | 149 | 110 | 7.19% | 797 | 0 | CDP |
| Bishop Hill | 40 | 111 | 113 | -0.89% | 208 | 1 | Village |
| Nekoma | 41 | 65 | 48 | 6.56% | 496 | 0 | CDP |
| Swedona | 42 | 40 | 95 | 8.11% | 141 | 0 | CDP |
| Lynn Center | 43 | 30 | 39 | 7.14% | 153 | 0 | CDP |
Kewanee is the largest city in Henry County, with a population of 12,065.
Lynn Center is the smallest city in Henry County, with a population of 30.
There are 43 cities in Henry County, Illinois.