Thunderbird reports in South Dakota
1 case, best-documented first. Page 1 of 1.
We map claims, not creatures. A case is what some source says someone saw or heard, with the link to that source. It is not proof that anything was there, and a retelling counts once, not as a second sighting.

Thunderbird · Scenic, South Dakota · 1923
Chief Flaming Arrow reports that the Thunder Bird dwelt in the Bad Lands area southwest of Scenic, S.D., which Indians call a 'bad place' and has never been visited by white men.