19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oquawka township | 1 | 1,557 | 1,654 | -1.14% | 64 | 24.22 | Township |
| Oquawka | 2 | 1,047 | 1,124 | -1.41% | 713 | 1.47 | Village |
| Stronghurst township | 3 | 993 | 1,070 | -1.59% | 28 | 35.92 | Township |
| Gladstone township | 4 | 762 | 810 | -1.17% | 16 | 46.81 | Township |
| Stronghurst | 5 | 757 | 817 | -1.56% | 867 | 0.87 | Village |
| Lomax township | 6 | 683 | 738 | -1.59% | 24 | 28.48 | Township |
| Biggsville township | 7 | 515 | 545 | -0.96% | 14 | 36.64 | Township |
| Lomax | 8 | 371 | 403 | -1.59% | 312 | 1.19 | Village |
| Media township | 9 | 332 | 355 | -1.19% | 9 | 36.41 | Township |
| Biggsville | 10 | 281 | 301 | -1.4% | 834 | 0.34 | Village |
| Carman | 11 | 244 | 187 | 7.02% | 597 | 0.41 | CDP |
| Raritan township | 12 | 234 | 248 | -0.85% | 7 | 34.01 | Township |
| Carman township | 13 | 227 | 238 | -0.87% | 10 | 21.95 | Township |
| Rozetta township | 14 | 217 | 237 | -2.25% | 6 | 36.34 | Township |
| Gladstone | 15 | 213 | 232 | -1.84% | 592 | 0.36 | Village |
| Bald Bluff township | 16 | 207 | 220 | -1.43% | 5 | 42.06 | Township |
| Terre Haute township | 17 | 201 | 220 | -2.43% | 6 | 35.96 | Township |
| Media | 18 | 109 | 118 | -1.8% | 64 | 1.70 | Village |
| Raritan | 19 | 95 | 102 | -1.04% | 1,000 | 0.10 | Village |
Oquawka township is the largest city in Henderson County, with a population of 1,557.
Raritan is the smallest city in Henderson County.
There are 19 cities in Henderson County, Illinois.