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 and was redesignated as the nation's 61st national park on February 15, 2019. The park runs for about 20 miles (32 km) along the southern shore of Lake Michigan and covers 15,349 acres (6,212 ha). 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 Cleveland-Cliffs steel plant on the west. This area's conservation scheme is enhanced by the older Indiana Dunes State Park. To the west of the steel plant lies West Beach and 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 Hoosier Prairie State Nature Preserve and the Hobart Prairie Grove, both in Lake County, the western end of the park.

The National Park Service (NPS) is an agency of the United States federal government, within the U.S. Department of the Interior. The service manages all national parks; most national monuments; and other natural, historical, and recreational properties, with various title designations. The United States Congress created the agency on August 25, 1916, through the National Park Service Organic Act. Its headquarters are in Washington, D.C., within the main headquarters of the Department of the Interior.