On March 25, 1803, the Ohio legislature established Gallia County. Gallia County was originally part of Washington County. Residents named the county after the kingdom of Gaul. This was a former name for much of what is now modern-day France. In 1790, several hundred French immigrants were persuaded by people representing the Scioto Company to come to the United States. They built a settlement in the Ohio Country that they called Gallipolis, meaning "city of the Gauls." The French settlers later discovered that the company's representatives had misled them. The land that they had purchased actually belonged to the Ohio Company of Associates rather than to the Scioto Company. Many of the immigrants returned to the East, but those who chose to stay either had to pay the Ohio Company for their land or move to an area set aside for them by the American government known as the French Grant. The people who purchased the land a second time were among the first white settlers in what later became Gallia County.
Gallia County is located in southeastern Ohio and is part of Appalachia. Its eastern border is on the Ohio River. The county is primarily rural and only 1.4 percent of its 469 square miles is urban. The county seat is Gallipolis and it is the second largest community in the county. The population of Gallipolis was just over 4,180 people in 2000. The county's largest township was Green Township, with a population of 5,514 people in 2000. Between 1995 and 2000, Gallia County experienced about a five percent population loss. Approximately 31,069 people lived in the county in 2000. This loss in population is typical of many of Ohio's more rural counties.
The largest employers in Gallia County are service industries and retail businesses. Among the larger employers is Rio Grande University. The Bob Evans Farm is also a major tourist attraction. It was at the farm that Bob Evans developed his successful restaurant business. In 1995, the per capita income in the county was 19,438 dollars. Over eighteen percent of the county's residents were living in poverty.
Most voters in Gallia County claim to be political independents.