Hell Creek Fossil Area
The Hell Creek formation and valley is the type locality for Tyrannosaurus rex, Ankylosaurus magniventris, and Brachychampsa fontana, the oldest known true alligator. The Hell Creek Fossil Area has also produced several specimen of Triceratops prorsus and is where over 95% of T. rex museum specimens have come from.
Year designated: 1966
Ownership: Federal, State, Private
Please remember, National Natural Landmarks (NNLs) are not national parks. NNLs are owned by a variety of public and private entities and allowing visitation is at their discretion. Many NNL sites maintain public websites where additional information may be found.