17 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gold Hill | 1 | 1,357 | 1,444 | -0.44% | 39 | 35 | Township |
| Shawneetown | 2 | 970 | 1,053 | -1.42% | 1,322 | 1 | City |
| Ridgway | 3 | 799 | 853 | -0.37% | 23 | 36 | Township |
| Ridgway | 4 | 783 | 848 | -1.39% | 890 | 1 | Village |
| Equality | 5 | 715 | 764 | -0.56% | 19 | 37 | Township |
| Equality | 6 | 492 | 534 | -1.4% | 561 | 1 | Village |
| New Haven | 7 | 414 | 439 | -0.48% | 9 | 44 | Township |
| North Fork | 8 | 400 | 427 | -0.74% | 11 | 36 | Township |
| Omaha | 9 | 391 | 419 | -0.51% | 21 | 19 | Township |
| New Haven | 10 | 369 | 398 | -1.34% | 297 | 1 | Village |
| Omaha | 11 | 200 | 217 | -1.48% | 269 | 1 | Village |
| Eagle Creek | 12 | 168 | 172 | 0.6% | 5 | 37 | Township |
| Shawnee | 13 | 163 | 172 | 0% | 7 | 24 | Township |
| Bowlesville | 14 | 152 | 152 | 1.33% | 4 | 39 | Township |
| Old Shawneetown | 15 | 101 | 110 | -0.98% | 198 | 1 | Village |
| Asbury | 16 | 95 | 103 | -1.04% | 5 | 18 | Township |
| Junction | 17 | 52 | 57 | -1.89% | 63 | 1 | Village |
Gold Hill is the largest city in Gallatin County, with a population of 1,357.
Junction is the smallest city in Gallatin County, with a population of 52.
There are 17 cities in Gallatin County, Illinois.