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.

Jackson County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 32,653. Its county seat is Jackson. The county is named for Andrew Jackson, a hero of the War of 1812 who was subsequently elected President of the United States. It is known as "The Little Wales of Ohio." Jackson County comprises the Jackson, OH Micropolitan Statistical Area.