19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oquawka | 1 | 1,572 | 1,658 | -0.88% | 65 | 24 | Township |
| Oquawka | 2 | 1,060 | 1,129 | -1.3% | 722 | 1 | Village |
| Stronghurst | 3 | 1,011 | 1,067 | -0.69% | 28 | 36 | Township |
| Gladstone | 4 | 768 | 811 | -0.9% | 16 | 47 | Township |
| Stronghurst | 5 | 762 | 812 | -1.3% | 873 | 1 | Village |
| Lomax | 6 | 691 | 741 | -1.43% | 24 | 28 | Township |
| Biggsville | 7 | 513 | 546 | -1.35% | 14 | 37 | Township |
| Lomax | 8 | 373 | 403 | -1.58% | 314 | 1 | Village |
| Media | 9 | 338 | 357 | -0.59% | 9 | 36 | Township |
| Biggsville | 10 | 283 | 301 | -1.39% | 840 | 0 | Village |
| Carman | 11 | 244 | 187 | 7.02% | 597 | 0 | CDP |
| Raritan | 12 | 234 | 248 | -0.85% | 7 | 34 | Township |
| Carman | 13 | 229 | 238 | -0.87% | 10 | 22 | Township |
| Rozetta | 14 | 222 | 235 | -0.89% | 6 | 36 | Township |
| Gladstone | 15 | 218 | 232 | -1.36% | 606 | 0 | Village |
| Bald Bluff | 16 | 208 | 217 | -0.95% | 5 | 42 | Township |
| Terre Haute | 17 | 205 | 217 | -0.97% | 6 | 36 | Township |
| Media | 18 | 109 | 117 | -1.8% | 64 | 2 | Village |
| Raritan | 19 | 96 | 103 | -2.04% | 1,011 | 0 | Village |
Oquawka is the largest city in Henderson County, with a population of 1,572.
Raritan is the smallest city in Henderson County, with a population of 96.
There are 19 cities in Henderson County, Illinois.