Few places on Earth carry as much dinosaur history as the Hell Creek Formation. Its rocks hold the last dinosaurs that lived before the extinction 66 million years ago, including Tyrannosaurus rex and Triceratops. For collectors, Hell Creek Formation fossils are among the most desirable dinosaur specimens in the world.
This guide explains where the formation is, how old it is, which dinosaurs it preserves and how to choose Hell Creek specimens for your collection.
Where is the Hell Creek Formation?
The Hell Creek Formation is exposed across eastern Montana, western North Dakota and northwestern South Dakota, with small exposures in Wyoming. Its grey, tan and banded clays and sandstones form rugged badlands, especially around Garfield County, Montana, and the area near Marmarth, North Dakota.
The formation takes its name from Hell Creek, near Jordan, Montana. Paleontologist Barnum Brown found the first recognised Tyrannosaurus rex skeleton in this area in 1902 and named the formation a few years later.
How old are Hell Creek fossils?
Hell Creek rocks date to the very end of the Cretaceous period, roughly 68 to 66 million years ago. The top of the formation is close to the Cretaceous–Paleogene (K-Pg) boundary, the thin layer that marks the asteroid impact and the extinction of the non-bird dinosaurs.
That makes Hell Creek a snapshot of the final ecosystem of the dinosaurs.
Dinosaurs of the Hell Creek Formation
| Group | Dinosaurs | What collectors usually find |
|---|---|---|
| Tyrannosaurs | Tyrannosaurus rex, Nanotyrannus | Shed teeth, occasional rooted teeth and bones |
| Horned dinosaurs | Triceratops, Torosaurus | Teeth, horn and frill fragments, bones |
| Duck-billed dinosaurs | Edmontosaurus | Teeth, vertebrae, toe bones, tendons |
| Armored dinosaurs | Ankylosaurus, Denversaurus | Teeth, osteoderms (armor plates) |
| Dome-headed dinosaurs | Pachycephalosaurus, Sphaerotholus | Teeth, dome fragments |
| Small plant-eaters | Thescelosaurus | Teeth and bones |
| Raptors | Acheroraptor, Dakotaraptor | Small serrated teeth, claws |
| Other theropods | Anzu, ornithomimids (Struthiomimus, Ornithomimus) | Claws and bones |
The formation also preserves crocodilians, turtles, champsosaurs, gar fish, early mammals and plant fossils, which helps scientists rebuild the whole ecosystem.
The status of Nanotyrannus has been debated for decades. Recent research, including work on the “Dueling Dinosaurs” specimen from Hell Creek, has strengthened the case that it was a separate small tyrannosaur rather than a juvenile T. rex.
What Hell Creek fossils can collectors buy?
- Theropod teeth. T. rex teeth are the headline fossil, with Nanotyrannus teeth and raptor teeth close behind.
- Triceratops fossils. Teeth, horn sections and bones from the most common large dinosaur in the formation. See the Triceratops collection.
- Edmontosaurus bones and teeth. Often the most accessible Hell Creek fossils, found in the hadrosaur category.
- Pachycephalosaur and Thescelosaurus teeth. Small, distinctive and great for a complete Hell Creek set. Browse Pachycephalosaurus and Thescelosaurus.
- Ankylosaur osteoderms and teeth. Armor plates are some of the most unusual pieces you can own. See ankylosaur fossils.
How to build a Hell Creek collection
A Hell Creek “ecosystem” collection is one of the most rewarding themes in the hobby.
- Start with an Edmontosaurus or Triceratops tooth. Common, affordable to begin with and easy to identify.
- Add a predator. A raptor tooth or a Nanotyrannus tooth brings in the meat-eaters.
- Add bones and armor. A hadrosaur vertebra or an ankylosaur osteoderm adds variety.
- Aim for a T. rex tooth. The centrepiece of any Hell Creek collection.
Buying tips for Hell Creek fossils
- Confirm the formation and state on every listing.
- Make sure the fossil came from private land; Hell Creek also covers federal land, where collecting for sale is illegal.
- Ask about repairs, especially on bones and large teeth.
- Check that the species fits the formation. A Daspletosaurus or Gorgosaurus tooth, for example, comes from older rocks and should not be labelled Hell Creek.
Frequently asked questions
1. What dinosaurs are found in the Hell Creek Formation?
Tyrannosaurus rex, Triceratops, Edmontosaurus, Ankylosaurus, Pachycephalosaurus, Thescelosaurus, raptors such as Acheroraptor, and others.
2. How old is the Hell Creek Formation?
About 68 to 66 million years old, from the very end of the Cretaceous period.
3. Where is the Hell Creek Formation located?
Mainly in eastern Montana, western North Dakota and northwestern South Dakota.
4. Are Hell Creek fossils legal to buy?
Yes, when they come from private land with the landowner’s permission.
5. What is the most common Hell Creek dinosaur fossil?
Triceratops and Edmontosaurus remains are among the most frequently found.
Own a piece of the last dinosaur world
Hell Creek fossils capture the final chapter of the dinosaurs in remarkable detail. Whether you start with a hadrosaur tooth or set your sights on T. rex, a well-documented specimen is a true piece of history. Explore Hell Creek dinosaur fossils at Buried Treasure Fossils.