| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Charleston | 1 | 17,441 | 17,574 | -0.14% | 1,921 | 9 | City |
| Mattoon | 2 | 16,608 | 16,857 | -0.35% | 1,610 | 10 | City |
| Oakland | 3 | 718 | 733 | -0.42% | 917 | 1 | City |
| Ashmore | 4 | 624 | 637 | -0.48% | 775 | 1 | Village |
| Humboldt | 5 | 352 | 360 | -0.56% | 1,026 | 0 | Village |
| Lerna | 6 | 214 | 221 | -0.93% | 1,861 | 0 | Village |
| Allenville | 7 | 128 | 134 | -0.78% | 210 | 1 | Village |
Charleston is the largest city in Coles County, with a population of 17,441.
Allenville is the smallest city in Coles County, with a population of 128.
There are 7 cities in Coles County, Illinois.