Gallia County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 29,220. Its county seat and largest village is Gallipolis. Named after the French people who originally settled there, its name “Gallia” is the Latin word for Gaul, the ancient region of Western Europe that included present day France. Gallia County is part of the Point Pleasant, WV-OH Micropolitan Statistical Area.