The Crow Creek massacre occurred around the mid-14th century AD between Native American groups at a site along the upper Missouri River in the South Dakota area; it is now within the Crow Creek Indian Reservation. Crow Creek Site, the site of the massacre near Chamberlain, is an archaeological site and a U.S. National Historic Landmark, located at coordinates 43°58′48″N 99°19′54″W. An excavation of part of the site was done in the 1950s, at the time of dam construction on the river. Additional excavations were conducted in 1978 and later.