French Island is a census-designated place (CDP) in La Crosse County, Wisconsin, United States. As of the 2020 census, French Island had a population of 4,284. It lies on an island of the same name, though they are not coextensive; a portion of the island is part of the city of La Crosse. All of the island is part of the La Crosse Metropolitan Statistical Area. French Island is part of the town of Campbell and contains all of its population, because the balance of Campbell is uninhabited.