42 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Montebello township | 1 | 3,244 | 3,327 | -0.31% | 88 | 36.76 | Township |
| West Point township | 2 | 3,021 | 3,195 | -1.11% | 85 | 35.72 | Township |
| Carthage township | 3 | 2,876 | 2,959 | -0.42% | 72 | 40.21 | Township |
| Hamilton | 4 | 2,653 | 2,742 | -0.67% | 745 | 3.56 | City |
| Carthage | 5 | 2,408 | 2,490 | -0.66% | 952 | 2.53 | City |
| Warsaw township | 6 | 1,461 | 1,505 | -0.41% | 224 | 6.52 | Township |
| Warsaw | 7 | 1,451 | 1,505 | -0.75% | 223 | 6.52 | City |
| La Harpe township | 8 | 1,345 | 1,382 | -0.37% | 36 | 37.31 | Township |
| La Harpe | 9 | 1,137 | 1,174 | -0.61% | 834 | 1.36 | City |
| Nauvoo township | 10 | 914 | 940 | -0.44% | 234 | 3.90 | Township |
| Nauvoo | 11 | 911 | 941 | -0.65% | 269 | 3.39 | City |
| Dallas City township | 12 | 843 | 872 | -0.59% | 55 | 15.37 | Township |
| Dallas City | 13 | 775 | 807 | -0.77% | 326 | 2.37 | City |
| Augusta township | 14 | 692 | 710 | -0.29% | 18 | 37.87 | Township |
| Chili township | 15 | 597 | 613 | -0.33% | 16 | 37.77 | Township |
| St. Mary township | 16 | 547 | 559 | -0.18% | 15 | 36.98 | Township |
| Augusta | 17 | 536 | 556 | -0.74% | 776 | 0.69 | Village |
| Bowen | 18 | 447 | 461 | -0.67% | 1,044 | 0.43 | Village |
| Sonora township | 19 | 435 | 447 | -0.23% | 12 | 35.79 | Township |
| Appanoose township | 20 | 423 | 432 | -0.24% | 17 | 25.52 | Township |
| Plymouth | 21 | 420 | 435 | -0.71% | 743 | 0.56 | Village |
| Prairie township | 22 | 376 | 385 | 0% | 11 | 33.07 | Township |
| Pontoosuc township | 23 | 334 | 342 | -0.3% | 18 | 18.47 | Township |
| Bear Creek township | 24 | 311 | 321 | -0.32% | 9 | 36.26 | Township |
| Rock Creek township | 25 | 306 | 318 | -0.65% | 9 | 35.97 | Township |
| St. Albans township | 26 | 299 | 307 | -0.33% | 8 | 36 | Township |
| Harmony township | 27 | 291 | 303 | -0.68% | 8 | 37.58 | Township |
| Rocky Run-Wilcox township | 28 | 278 | 291 | -1.07% | 5 | 56.80 | Township |
| Walker township | 29 | 278 | 287 | -0.36% | 7 | 37.98 | Township |
| Hancock township | 30 | 247 | 251 | 0% | 6 | 38.15 | Township |
| Durham township | 31 | 241 | 254 | -1.23% | 7 | 36.91 | Township |
| Wythe township | 32 | 238 | 248 | -0.83% | 6 | 38.08 | Township |
| Fountain Green township | 33 | 237 | 243 | -0.42% | 6 | 37.52 | Township |
| Pilot Grove township | 34 | 237 | 247 | -0.84% | 6 | 36.97 | Township |
| Hamilton township | 35 | 175 | 182 | -1.13% | 5 | 35.73 | Township |
| Elvaston | 36 | 143 | 148 | -0.69% | 179 | 0.80 | Village |
| West Point | 37 | 136 | 141 | -0.73% | 810 | 0.17 | Village |
| Ferris | 38 | 118 | 127 | -1.67% | 60 | 1.97 | Village |
| Pontoosuc | 39 | 98 | 102 | -1.01% | 70 | 1.41 | Village |
| Basco | 40 | 75 | 79 | -1.32% | 338 | 0.22 | Village |
| Bentley | 41 | 25 | 27 | 0% | 175 | 0.14 | Town |
| Niota | 42 | 16 | 85 | 6.67% | 31 | 0.52 | CDP |
Montebello township is the largest city in Hancock County, with a population of 3,244.
Niota is the smallest city in Hancock County.
There are 42 cities in Hancock County, Illinois.