Indiana Dunes National Lakeshore is a unit of the National Park System designated as a U.S. National Lakeshore located in northwest Indiana and managed by the National Park Service. It was authorized by Congress in 1966. The national lakeshore runs for nearly 25 miles along the southern shore of Lake Michigan, in Chesterton, Indiana. The park contains approximately 15,000 acres. The National Lakeshore has acquired about 95% of the property within the authorized boundaries.