17 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gold Hill | 1 | 1,363 | 1,444 | -0.44% | 39 | 35 | Township |
| Shawneetown | 2 | 984 | 1,053 | -1.4% | 1,341 | 1 | City |
| Ridgway | 3 | 802 | 853 | -0.37% | 23 | 36 | Township |
| Ridgway | 4 | 794 | 848 | -1.37% | 902 | 1 | Village |
| Equality | 5 | 719 | 764 | -0.55% | 20 | 37 | Township |
| Equality | 6 | 499 | 534 | -1.38% | 569 | 1 | Village |
| New Haven | 7 | 416 | 439 | -0.48% | 10 | 44 | Township |
| North Fork | 8 | 403 | 427 | -0.74% | 11 | 36 | Township |
| Omaha | 9 | 393 | 419 | -0.51% | 21 | 19 | Township |
| New Haven | 10 | 374 | 398 | -1.32% | 301 | 1 | Village |
| Omaha | 11 | 203 | 217 | -1.46% | 273 | 1 | Village |
| Eagle Creek | 12 | 167 | 172 | 0.6% | 5 | 37 | Township |
| Shawnee | 13 | 163 | 172 | 0% | 7 | 24 | Township |
| Bowlesville | 14 | 150 | 152 | 1.35% | 4 | 39 | Township |
| Old Shawneetown | 15 | 102 | 110 | -1.92% | 200 | 1 | Village |
| Asbury | 16 | 96 | 103 | -1.03% | 5 | 18 | Township |
| Junction | 17 | 53 | 57 | -1.85% | 64 | 1 | Village |
Gold Hill is the largest city in Gallatin County, with a population of 1,363.
Junction is the smallest city in Gallatin County, with a population of 53.
There are 17 cities in Gallatin County, Illinois.