Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Quincy | 1 | 38,600 | 39,410 | -0.52% | 2,448 | 15.8 | City |
| Camp Point | 2 | 1,111 | 1,123 | -0.27% | 878 | 1.3 | Village |
| Payson | 3 | 992 | 1,022 | -0.8% | 848 | 1.2 | Village |
| Mendon | 4 | 845 | 869 | -0.7% | 986 | 0.9 | Village |
| Golden | 5 | 625 | 645 | -0.79% | 974 | 0.6 | Village |
| Clayton | 6 | 615 | 638 | -0.97% | 696 | 0.9 | Village |
| Ursa | 7 | 587 | 607 | -0.84% | 851 | 0.7 | Village |
| Liberty | 8 | 522 | 541 | -0.95% | 1,335 | 0.4 | Village |
| Loraine | 9 | 292 | 298 | -0.68% | 346 | 0.8 | Village |
| Plainville | 10 | 263 | 271 | -0.76% | 1,119 | 0.2 | Village |
| Paloma | 11 | 147 | 174 | 8.09% | 505 | 0.3 | CDP |
| Coatsburg | 12 | 143 | 147 | -0.69% | 1,083 | 0.1 | Village |
| Lima | 13 | 143 | 147 | -0.69% | 1,059 | 0.1 | Village |
| Burton | 14 | 130 | 41 | 8.33% | 394 | 0.3 | CDP |
| Bloomfield | 15 | 114 | 99 | 7.55% | 219 | 0.5 | CDP |
| Columbus | 16 | 111 | 114 | -0.89% | 507 | 0.2 | Village |
| Fowler | 17 | 96 | 86 | 7.87% | 711 | 0.1 | CDP |
| Beverly | 18 | 82 | 110 | 7.9% | 60 | 1.4 | CDP |
| El Dara | 19 | 61 | 64 | -1.61% | 60 | 1.0 | Village |
| Adams | 20 | 46 | 44 | 9.52% | 21 | 2.2 | CDP |
| Marcelline | 21 | 41 | 76 | 7.9% | 820 | 0.1 | CDP |
| La Prairie | 22 | 38 | 40 | -2.56% | 197 | 0.2 | Village |
| Meyer | 23 | 22 | 0 | 4.76% | 155 | 0.1 | CDP |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Quincy is the largest city in Adams County.
Meyer is the smallest city in Adams County.
There are 23 cities in Adams County, Illinois.