Galesville is a city in Trempealeau County, Wisconsin, United States. The population was 1,662 at the 2020 census. A dam on Beaver Creek is …Galesville is a city in Trempealeau County, Wisconsin, United States. The population was 1,662 at the 2020 census. A dam on Beaver Creek is located at Galesville, forming Lake Marinuka north of the city. The mayor is Vince Howe.