Water Monster reports in Pennsylvania
2 cases, 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 · Masontown, Pennsylvania · 1897
A 20-foot river monster is reported to have frightened fishermen along the Monongahela River near Masontown.

Water Monster · Carbon County, Pennsylvania · 1886
Witnesses report seeing a sea serpent on the Lehigh River, describing it as seventeen feet long with a head like a beer keg.