Water Monster reports from the 1820s
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.

Water Monster · Fort Snelling Unorganized Territory, Minnesota · 1827
Mrs. [name] reports that in 1827 at Fort Snelling, a huge water monster was greeted with wild whoops by Indians.