6 Dinosaurs That Lived in Idaho (And Where to See Fossils Today)

Written by Kyle Glatz
Updated: July 18, 2023
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Although Idaho is close to Montana, one of the states with the greatest number of dinosaur fossil finds, scientists have recovered relatively few fossils in this area. Much of Idaho spent at least some time underwater while dinosaurs roamed the planet. However, we do know about at least six different dinosaurs that lived in Idaho.

Learn about the different types of dinosaurs that once roamed the land. Scientists have evidence of some particular dinosaurs along with evidence of certain dinosaur families.  

Dinosaurs Idaho
Many types of dinosaur bones have been identified in Idaho.

What Is Idaho’s State Dinosaur?

Idaho does not have a state dinosaur, but it does have a state fossil. The state fossil of Idaho is the Hagerman horse, Equus simplicidens. This creature is also referred to as the Hagerman Zebra or the American Zebra. The creature obtained its name from the location where it was found: Hagerman, Idaho.

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Scientists believed that this creature once lived in the open grasslands in Idaho and other states about 3.7 million years ago. This creature is believed to be one of the first species in the Equus genus, and that means it could be an ancestor to most modern horses.

Paleontologists have recovered over 200 sets of Hagerman horse remains throughout the U.S. Some of them are complete and others are partial, but they have given people a great level of insight into these creatures.  

What Are the 6 Dinosaurs That Lived in Idaho?

Although paleontologists and geologists haven’t recovered much fossils throughout Idaho, several genera once called this place home. The available evidence suggests that at least six types of dinosaurs called this place home, but many others probably lived in Idaho throughout its long history.

Unfortunately, the conditions in prehistoric Idaho were not always the best for preserving fossils until the Cretaceous era. Even then, some parts of the state were still below water.

As a result, dinosaur findings have been somewhat of a mixed bag. Scientists have found evidence of certain species in Idaho. Yet, some fossils only allowed dinosaurs to discover the order or family that the ancient creatures belonged to rather than their species.

Let’s take a look at some of the dinosaurs that lived in Idaho throughout the state’s long history.  

1. Oryctodromeus


This small creature roamed around Idaho several million years ago.

©FunkMonk (Michael B. H.), CC BY-SA 3.0 – License

Oryctodromeus was a dinosaur known for being a small, fast creature that would dig burrows for protection and for raising its young. In fact, this species was the first dinosaur ever to be discovered to demonstrate burrowing behavior. These small dinosaurs were bipedal, weighed about 50 to 70 pounds, and measured close to 7 feet long.

Although it’s easy to read about this creature and imagine a series of quick carnivores emerging from a burrow to hunt, this species was probably herbivorous. Dinosaur remains from this species have been found in both Montana and Idaho.

2. Oviraptoridae


Many types of Oviraptors roamed around the earth, including in Idaho.

©PaleoNeolitic, CC BY 4.0 – License

The name “Oviraptoridae” refers to a rather diverse group of dinosaurs that lived throughout North America and Asia. This group varies in many ways. Some of them are about the size of a modern-day turkey, while others, like Gigantoraptor, weigh over a ton. They may have consumed plants, mollusks, or even the eggs of other creatures.  

However, the Idaho Oviraptorid is a type of these dinosaurs found in the Wayan Formation that could have been roughly the size of a large dog. They weighed about 2.5 feet tall at the hips and 11 feet long, with most of that length coming from their tails.

Although they can range in size, oviraptorosaurs are known for being closely related to modern birds, having short, beaked skulls. Some species, including the one from Idaho, are known only by their fossilized eggs rather than recovered bones.

3. Tenontosaurus dossi


Tenontosaurus weighed between 1,300 to 2,200 pounds.

©Herschel Hoffmeyer/Shutterstock.com

Tenontosaurus was a genus of ornithopods that lived between 115 million and 108 million years ago. This dinosaur was herbivorous and lived in an area that was rife with carnivores. This creature was medium or large, growing over 20 feet long and weighing somewhere between 1,000 and 2,200 pounds.

4. Ceratopsians


The neoceratopsia may have looked something like this.

©Ralf Juergen Kraft/Shutterstock.com

Certatopsia is a group of dinosaurs known for the horns on its head as well as a beak-like mouth. An example of this dinosaur would be the Triceratops, but that is not the species of dinosaur found in Idaho. Instead, scientists found evidence from the clade Neoceratopsia, a subset of the group.  

Evidence of this dinosaur’s existence is scant, but we know that it was almost certainly a large, thick-bodied quadrupedal herbivore.

5. Unidentified Theropods


This is a close approximation of what the Oryctodromeus probably looked like.

©FunkMonk (Michael B. H.), CC BY-SA 3.0 – License

Sometimes, scientists can find the precise genus or species to which a dinosaur belongs, like a theropod we’ve already named, Oryctodromeus. However, that’s not always the case. Paleontologists have found fragmentary evidence of theropod dinosaurs, such as teeth. However, that is not enough evidence to identify the creatures in most cases.

In 2022, scientists recovered a thigh bone of a type of tyrannosaur, but it was much smaller than a T-rex, and the species has not yet been identified.

6. Ankylosaurus

A fossil of the Ankylosaurus was found in Idaho.


A single fossil of an unidentified Ankylosaurus was recovered in Idaho, offering some proof that members of this genus once lived in the state. These heavy, armored herbivores lived toward the end of the Cretaceous Period, between 68 million and 66 million years ago.

Where Can You See Dinosaur Fossils in Idaho?

A few options exist for people that would like to see fossils in Idaho. Yet, it’s difficult to find a place to see dinosaur fossils. If you want to see fossils of the Hagerman horse and large mammals from a few million years ago, the Hagerman Fossil Beds and its associated visitor center are a great place to stop. You can see fossil exhibits on display at the visitor center and more.

The Idaho Museum of Natural History is another great place to see fossils from the state. However, given the fragmentary nature of many of the dinosaur fossil finds in this state, they do not have an ongoing dinosaur fossil exhibit. Take some time to look at the upcoming exhibits for the museum before you plan a trip so you can get the most out of your journey.

Summary of 6 Dinosaurs That Lived in Idaho (And Where to See Fossils Today)

Here’s a recap of 6 dinosaurs that once inhabited the state of Idaho:

3Tenontosaurus dossi
5Unidentified Theropods

The photo featured at the top of this post is © Daniel Eskridge/Shutterstock.com

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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