6 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gallipolis | 1 | 3,263 | 3,319 | -0.28% | 907 | 4 | Village |
| Rio Grande | 2 | 726 | 720 | 0.14% | 528 | 1 | Village |
| Crown City | 3 | 414 | 422 | -0.24% | 357 | 1 | Village |
| Vinton | 4 | 223 | 223 | 0% | 189 | 1 | Village |
| Cheshire | 5 | 120 | 123 | 0% | 156 | 1 | Village |
| Centerville (Thurman) | 6 | 86 | 88 | 0% | 860 | 0 | Village |
Gallipolis is the largest city in Gallia County, with a population of 3,263.
Centerville (Thurman) is the smallest city in Gallia County, with a population of 86.
There are 6 cities in Gallia County, Ohio.