Barnesville is a city in Lamar County, Georgia, United States. The city is a part of the Atlanta Metropolitan Area. As of the 2010 census, the city had a population of 6,755. The city is the county seat of Lamar County.
Barnesville was founded in 1826 and named for local tavern owner Gideon Barnes. In 1920, Barnesville was designated seat of the newly formed Lamar County.Barnesville served as a major hospital site for wounded southern troops during the Civil War. Local families took wounded soldiers into their homes and treated them, with highly successful recovery rates. Major General William B. Bate, CSA of Hardees Corps., wounded in Atlanta at Utoy Creek on August 10, 1864, was treated here. After the war, General Bate was elected Governor of Tennessee and served in the United States Senate until his death in 1912. He commented on his successful recovery as a result of the kindness of the local populace in Barnesville.