Donalsonville is a city in and the county seat of Seminole County, Georgia, United States. The population was 2,833 in 2020. Donalsonville was originally part of Decatur County. It is named after John Ernest Donalson, also known as Jonathan or John E. Donalson, a prominent businessman of the area. Donalson built the first lumber mill in Donalsonville, Donalson Lumber Company. He also built homes and a commissary for the workers of the mill. The lumber company paved the way for the town's growth.