Indiana Dunes National Park is a United States National Park located in Northwestern Indiana, managed by the National Park Service. It was authorized by Congress in 1966 as the Indiana Dunes National Lakeshore, the name by which it was known until it was designated the nation's 61st national park on February 15, 2019. The park runs for nearly 25 miles along the southern shore of Lake Michigan; it contains approximately 15,000 acres. Its visitors center is in Porter, Indiana. Located in the park are sand dune, wetland, prairie, river, and forest ecosystems.
Indiana Dunes National Park has acquired about 95% of the property within the authorized boundaries. Several of its holdings are non-contiguous and do not include the 2,182-acre Indiana Dunes State Park, which is within the boundaries of the national park but is owned, managed, and protected by the state of Indiana. The national park is divided into 15 parcels of various acreage. Along the lakefront, the eastern area is roughly the lake shore 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 in 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 the Hobart Prairie Grove, both in Lake County, the western end of the park. Also within the National Park is the Hoosier Prairie State Nature Preserve, managed by the Indiana Department of Natural Resources.