| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Dahlgren | 1 | 493 | 503 | -0.4% | 485 | 1 | Village |
| Broughton | 2 | 179 | 183 | -0.56% | 95 | 2 | Village |
| Belle Prairie City | 3 | 46 | 48 | -2.13% | 105 | 0 | Town |
| Macedonia | 4 | 27 | 27 | 0% | 99 | 0 | Village |
Dahlgren is the largest city in Hamilton County, with a population of 493.
Macedonia is the smallest city in Hamilton County, with a population of 27.
There are 4 cities in Hamilton County, Illinois.