| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hardin | 1 | 775 | 795 | -0.51% | 364 | 2 | Village |
| Kampsville | 2 | 292 | 302 | -0.68% | 286 | 1 | Village |
| Batchtown | 3 | 165 | 171 | -0.6% | 89 | 2 | Village |
| Brussels | 4 | 110 | 113 | -0.9% | 196 | 1 | Village |
| Hamburg | 5 | 94 | 98 | -1.05% | 180 | 1 | Village |
Hardin is the largest city in Calhoun County, with a population of 775.
Hamburg is the smallest city in Calhoun County, with a population of 94.
There are 5 cities in Calhoun County, Illinois.