Fossils in Montana and the Dakotas

What are fossils?

Where are fossils found?

What types of fossils are found in Montana, North Dakota, and South Dakota?

Help protect your fossils. 

What are fossils?

Tyrannosaurid toothFossils include all evidence of past life. Some fossils are those that people commonly think of when they hear the word, things like leaves, bones, teeth, and shells from once-living organisms. But fossils also include other evidence of an organism’s presence, such as footprints, burrows, impressions, even fossilized feces—all of them are fossils too!

Fossils are the ONLY source of information about past life. Without them, we would never know about the great dinosaurs or cool marine reptiles that once lived where we do today. If you, or your children, know about prehistoric beasts, you owe that to fossils that were collected and studied by a scientist. The scientists that study fossils are called paleontologists (not to be confused with archaeologists, who study past human cultures; see information on the Billings Curation Center).

Most individual animals that ever lived did not die in such a way that their body would be preserved as a fossil. And fewer individuals still will have survived for millions of years and avoid erosion to be collected by a knowledgeable person. For these reasons, fossils are considered a rare and non-renewable resource.


Where are fossils found?

Most fossils represent organisms that lived a long time ago, and left evidence of their presence in the sediment around them. For example, maybe they died and were buried at the bottom of an ocean in the mud, or along a river. Over time, the sediment is turned to rock with the fossil inside, and after millions of years it might be eroding out at the surface just in time for you to find it sticking out of the side of the hill!

Therefore, most fossils are found in sedimentary rocks that preserve the environments in which prehistoric organisms lived. Common environments that collected sediments and fossils include seas and oceans, lakes, rivers, caves, watering holes, and other similar places where plants and animals might live.

So to find a fossil today, you want to look for places where sedimentary rocks are exposed at the surface, where erosion might expose new fossils.


What types of fossils are found in Montana, North Dakota, and South Dakota?

Highway sign about dinosaurs near Bridger, MontanaMany of the most exciting fossils you can see in museums today were collected from land managed by the BLM. Montana and the Dakotas include some of the richest fossil-bearing rocks in the world. Eastern Montana and the Dakotas have extensive exposures of dinosaur-rich rocks and have produced many important fossils of the world’s most famous dinosaurs, animals like Tyrannosaurus, Triceratops, hadrosaurs, and many others. Those fossils come from rocks of Late Jurassic (~150 million) to Late Cretaceous (~65 million) age.

In addition, many sea creatures can be found across the region. Long-necked plesiosaurs, animals described as looking like you threaded a snake through the body of a turtle, have been found. As well as flying reptiles, and the lizards of the seas, mosasaurs.

Across the western part of Montana, many fossils have been found in younger-aged rocks in the intermontane basins. Animals from several geologic ages from the last 65 million years are represented, including many unusual primitive mammal groups.



Help Protect Your Fossils

Casual collection of some fossils are allowed for personal, non-commercial use. See the details on hobby collecting. It is your responsibility to be familiar with the laws and regulations before you begin to collect. You should contact the closest Montana BLM Field Office for clarification and to learn about areas that are closed to collection.

Remember, fossils are part of our national heritage, and should be enjoyed responsibly. The BLM wants everyone to enjoy our public lands and resources in such a way that they are there for future generations. If you notice any suspicious activity on your public lands, with regard to fossils or any other resource, please contact Montana's BLM Law Enforcement at 406-896-5010.





State of Montana Indemnity GIS Data

Permitting and Contact

Educational Resources

Partners in Paleontology


Eastern Montana BLM dinosaur tours Japan

Montana fossils educate far away

New lizards found

Fossil Outreach in the Bridger Area

BLM Montana/Dakotas Paleontologist Greg Liggett talks Paleontology on Q2 - Video





BLM Montana/Dakotas Paleontologist Greg Liggett talks Paleontology on Q2