Crow Creek massacre

The Crow Creek massacre occurred around the mid 1300s CE between Native American groups at a site along the 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, with additional excavations in 1978 and later.
Two groups occupied the site in prehistoric times. The Siouan-speaking Middle Missouri people , ancestral to the historic Mandan people, first occupied the site sometime after about 900 AD. They built numerous earth lodges on the lower portion of the site. Caddoan-speaking Central Plains people moved into the area from southern areas sometime around 1150 AD. Whether they displaced the earlier group or moved on to an abandoned site is unknown. The Central Plains people built at least 55 lodges, mostly on the upper part of the site. There is no direct evidence that there was conflict between the two groups, and scholars have found evidence that both cultures changed gradually in relation to the other.

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