Lewistown (Assiniboine: Wá ską́šį diʾóda ) is a city in and the county seat of Fergus County, Montana, United States. The population was 5,901 at the 2010 census. Lewistown is located in central Montana, the geographic center of the state, southeast of Great Falls. First planned in 1882, it was the site of an 1880s gold rush.