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 (40 km) along the southern shore of Lake Michigan, in Beverly Shores, Indiana. The park contains approximately 15,000 acres.
The National Lakeshore has acquired about 95% of the property within the authorized boundaries. The National Lakeshore holdings are non-contiguous and includes the 2,182-acre Indiana Dunes State Park (1916), which is owned and managed by the state of Indiana in Beverly Shores, Indiana.
The park is physically divided into 15 disconnected pieces. Along the lakefront, the eastern area is roughly the lakeshore south to U.S. 12 or U.S. 20 between Michigan City, Indiana on the east and the ArcelorMittal steel plant on the west. A small extension, south of the steel mill continues west along Salt Creek to Indiana 249.
The western area is roughly the shoreline south to U.S. 12 between the Burns Ditch west to Broadway, downtown Gary, Indiana. In addition, there are several outlying areas, including; Pinhook Bog, in LaPorte County to the east. The Heron Rookery in Porter County, the center of the park, and the Calumet Prairie State Nature Preserve and Hobart Prairie Grove, both in Lake County, the western end of the park. Also within the National Lakeshore is the Hoosier Prairie State Nature Preserve, managed by the Indiana Department of Natural Resources.