43 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kewanee | 1 | 12,064 | 12,458 | -0.65% | 1,828 | 6.60 | City |
| Kewanee township | 2 | 9,491 | 9,756 | -0.41% | 262 | 36.16 | Township |
| Geneseo township | 3 | 7,496 | 7,550 | -0.2% | 207 | 36.28 | Township |
| Colona township | 4 | 6,591 | 6,698 | -0.17% | 228 | 28.92 | Township |
| Geneseo | 5 | 6,515 | 6,540 | -0.08% | 1,383 | 4.71 | City |
| Colona | 6 | 4,937 | 5,036 | -0.4% | 1,293 | 3.82 | City |
| Wethersfield township | 7 | 3,699 | 3,794 | -0.38% | 104 | 35.56 | Township |
| Western township | 8 | 2,862 | 2,927 | -0.31% | 81 | 35.48 | Township |
| Galva township | 9 | 2,639 | 2,709 | -0.42% | 77 | 34.28 | Township |
| Galva | 10 | 2,384 | 2,459 | -0.63% | 862 | 2.77 | City |
| Cambridge township | 11 | 2,368 | 2,423 | -0.25% | 64 | 36.93 | Township |
| Hanna township | 12 | 2,344 | 2,393 | -0.3% | 122 | 19.17 | Township |
| Cambridge | 13 | 2,021 | 2,085 | -0.64% | 1,015 | 1.99 | Village |
| Orion | 14 | 1,708 | 1,755 | -0.52% | 1,827 | 0.94 | Village |
| Phenix township | 15 | 1,652 | 1,691 | -0.36% | 50 | 32.84 | Township |
| Atkinson township | 16 | 1,205 | 1,237 | -0.41% | 34 | 35.15 | Township |
| Oxford township | 17 | 1,125 | 1,155 | -0.35% | 32 | 35.59 | Township |
| Orion township | 18 | 1,097 | 1,143 | -0.99% | 30 | 36.44 | Township |
| Annawan township | 19 | 1,086 | 1,118 | -0.46% | 30 | 36.32 | Township |
| Atkinson | 20 | 926 | 956 | -0.64% | 486 | 1.91 | Town |
| Andover township | 21 | 858 | 886 | -0.58% | 23 | 36.56 | Township |
| Annawan | 22 | 855 | 884 | -0.7% | 399 | 2.14 | Town |
| Clover township | 23 | 828 | 848 | -0.24% | 24 | 34.94 | Township |
| Lynn township | 24 | 773 | 788 | -0.26% | 21 | 36.27 | Township |
| Woodhull | 25 | 728 | 753 | -0.68% | 829 | 0.88 | Village |
| Alpha | 26 | 648 | 672 | -0.77% | 2,084 | 0.31 | Village |
| Edford township | 27 | 639 | 652 | -0.31% | 23 | 27.38 | Township |
| Andover | 28 | 532 | 554 | -0.75% | 537 | 0.99 | Village |
| Yorktown township | 29 | 430 | 438 | 0% | 12 | 35.73 | Township |
| Osco township | 30 | 410 | 424 | -0.73% | 11 | 36.48 | Township |
| Weller township | 31 | 393 | 395 | 0.26% | 11 | 34.35 | Township |
| Munson township | 32 | 356 | 362 | -0.28% | 10 | 35.94 | Township |
| Cornwall township | 33 | 255 | 258 | 0% | 7 | 35.59 | Township |
| Ophiem | 34 | 238 | 180 | 7.21% | 201 | 1.18 | CDP |
| Burns township | 35 | 233 | 238 | -0.43% | 6 | 36.46 | Township |
| Hooppole | 36 | 170 | 179 | -1.16% | 457 | 0.37 | Village |
| Alba township | 37 | 166 | 171 | -0.6% | 5 | 35.94 | Township |
| Cleveland | 38 | 157 | 162 | -0.63% | 534 | 0.29 | Village |
| Osco | 39 | 149 | 110 | 7.19% | 797 | 0.19 | CDP |
| Bishop Hill | 40 | 113 | 113 | 0% | 212 | 0.53 | Village |
| Nekoma | 41 | 65 | 48 | 6.56% | 496 | 0.13 | CDP |
| Swedona | 42 | 40 | 95 | 8.11% | 141 | 0.28 | CDP |
| Lynn Center | 43 | 30 | 39 | 7.14% | 153 | 0.20 | CDP |
Kewanee is the largest city in Henry County, with a population of 12,064.
Lynn Center is the smallest city in Henry County.
There are 43 cities in Henry County, Illinois.