The origins of the Mandan people of North Dakota are shrouded in legend and mystery. Were Vikings there 600 years ago?
Viking Settlement and the Mandans
"[Viking] journeys did result in one very probable legacy - the creation of a mixed race called the Mandans".
An article from the "Roundup Record-Tribune & Winnett Times" (Roundup, Montana) of March 27, 1941.
An Indian Winter
This book by Russell Freedman recounts the 1833 expedition of German prince Maximilian of Wied and Swiss artist Karl Bodmer.
Knife River Indian Village
The National Park Service site for these Mandan and Hidatsa villages.
A brief report of Lewis & Clark's 1804 encounter with them, from PBS.
The Mandan Mystery
A lengthy examination of the controversy by Charles W. Moore, with particular emphasis on the Kensington Stone.
The legend of a Welsh prince, Madog ab Owain Gwynedd, who discovered America in about 1170, and whose descendants are the Mandan.
That Mandan is not Welsh
A detailed article by Chris Harvey at the site Languagegeek.
This article by Roberta Jestes states that there is no known evidence of Mandan-Viking contact, and that "the theory is not supported generally by members of the intellectual establishment such as anthropologists and professional historians".