Primary source
Hell Creek: Triceratops central
The Hell Creek Formation is the core Triceratops formation represented on Fossil Atlas. Stretching across eastern Montana, the Dakotas, and northeastern Wyoming, these latest Cretaceous river deposits have yielded skulls, partial skeletons, and isolated elements. Triceratops appears frequently in Hell Creek discussions, but this page stays focused on selected modern discovery records rather than trying to count every specimen.