10 U.S. National Parks Where You Can Find Real Fossils
For millions of years, the land we now call the United States has been home to towering prehistoric beasts, strange sea creatures, and lush ancient forests that no longer exist. Evidence of this long-lost world is still embedded in rock layers, waiting to be discovered. While some national parks are famous for their fossils, others keep their prehistoric secrets tucked away in places most visitors overlook. The parks discussed in this article still hold traces of a past so ancient it’s hard to fathom.
Abraham Lincoln Birthplace National Historical Park, Kentucky
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Before Kentucky was home to Abraham Lincoln’s family, it was covered by a warm, shallow sea. The limestone bedrock beneath the rolling hills dates back more than 350 million years to the Mississippian period. If you look closely at rocky outcrops or streambeds, you might spot fossilized crinoids, sometimes called “sea lilies,” which once swayed with ocean currents like underwater flowers. Brachiopods, ancient-shelled creatures that resemble clams, are also common in the area.
Acadia National Park, Maine
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Beneath Maine’s rugged and dramatic coastline lies a story even older than the cliffs themselves. Some of the park’s oldest rock formations, including the Ellsworth Schist, hold fossilized trilobites—hard-shelled arthropods that scuttled along the seafloor over 500 million years ago. These creatures, now extinct, were some of the earliest complex animals on Earth. While fossils in Acadia aren’t as obvious as in some western parks, those who know where to look can find tiny imprints of ancient marine life preserved in stone.
Agate Fossil Beds National Monument, Nebraska
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This spot in Nebraska is famous for its fossilized remains of early mammals that roamed the plains around 20 million years ago. The land was once home to strange creatures like the Menoceras, a small two-horned rhinoceros, and the fierce Dinohyus, a massive pig-like beast. The best part is that the visitor center has some incredible displays of these fossils, which makes it easy to imagine the prehistoric world they once inhabited.
Alibates Flint Quarries National Monument, Texas
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For thousands of years, people have come to this site in the Texas Panhandle to mine its colorful, glassy flint. This rock that provided tools for early inhabitants also holds an even older treasure—fossils from the Permian period, more than 250 million years ago. Hidden within the dolomite are remains of ancient sea creatures, including delicate bryozoans and brachiopods that thrived in a prehistoric ocean that once covered this part of Texas.
Allegheny Portage Railroad National Historic Site, Pennsylvania
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The rolling hills of Pennsylvania hold more than just the story of early railroads that once carried canal boats over the Allegheny Mountains. The rocks in this region date back to the Paleozoic era and are packed with plant fossils from ancient, dense and swamp forests. These plants eventually became the coal that fueled the region’s industrial growth.
Amistad National Recreation Area, Texas
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While Amistad is known for its deep, blue reservoir and rugged canyon walls, those same cliffs tell a story that stretches back over 100 million years. The limestone formations here are packed with fossils from the Cretaceous period when this part of Texas lay beneath a vast inland sea. Fossilized ammonites, ancient relatives of squid with coiled shells, are embedded in the rock, along with the remains of other marine creatures that once swam through the waters above what is now desert.
Anacostia Park, Washington, D.C.
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While it may be hard to imagine fossils in the middle of a big city, Anacostia Park does have one known fossil in its collection—a quartzite cobble containing tube burrows made by ancient worms called Skolithos linearis. This fossil, likely transported from western Maryland by river systems, dates back to the Cambrian period, around 530 million years ago. Although the park itself does not contain preserved plant fossils or evidence of ancient forests, its geological history is still an interesting part of the region’s natural past.
Aniakchak National Monument and Preserve, Alaska
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This remote, wild park on the Alaska Peninsula is best known for its massive volcanic caldera as well as the fossilized record of marine life from long before the volcanoes erupted. Fossils found in the sedimentary rock layers include remnants of shellfish and other sea creatures from an ancient ocean world as well as dinosaur tracks and plant fossils.
Antietam National Battlefield, Maryland
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Beyond its Civil War history, the rolling hills of Maryland hold fossils that date back much further than the 19th century. The limestone and shale formations here contain marine fossils from over 400 million years ago when the region was submerged beneath an ancient sea. Fossils of trilobites, brachiopods, and other seafloor creatures can be found in the area.
Apostle Islands National Lakeshore, Wisconsin
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The dramatic cliffs and sea caves of the Apostle Islands tell a geologic story stretching back over a billion years. Some of the oldest rock formations here contain stromatolites—layered fossils created by cyanobacteria, some of the earliest life forms on Earth. These fossils provide a direct link to the planet’s earliest ecosystems.
Arches National Park, Utah
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While most people visit Arches to see its famous sandstone formations, the park also has traces of prehistoric life hidden in its rock layers. Tracks left by dinosaurs in the Entrada and Navajo Sandstone formations offer a reminder that this arid, wind-carved landscape was once home to giant reptiles that roamed long before the rock formations took shape.
Badlands National Park, South Dakota
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The Badlands are one of the most famous fossil destinations in the country, and for good reason. This eroded landscape has revealed some of the best-preserved fossils from the Oligocene epoch, around 30 million years ago. Fossils of ancient horses, rhinos, and even early camels have been found here, and it’s one of the best places to see prehistoric mammal fossils in North America.
Bandelier National Monument, New Mexico
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Bandelier holds traces of life that predate human history. Fossilized plants and small marine organisms have been found within the Bandelier Tuff, a volcanic rock formation that formed after massive eruptions millions of years ago. The fossils help tell the story of how this landscape changed long before people built homes on the cliffs.
Aztec Ruins National Monument, New Mexico
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Despite its name, this site has no connection to the Aztecs—but it does have a fascinating mix of human and natural history. The surrounding sedimentary rocks contain fossils from the Cretaceous period, including ammonites and mollusks, during a time when this region was covered by an inland sea.
Petrified Forest National Park, Arizona
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Fossils aren’t just bones and teeth—sometimes, they’re entire forests frozen in time. Petrified Forest National Park is a place where trees from the Triassic Period, over 200 million years ago, have turned to stone. These ancient logs once lined the banks of a river, only to be buried by volcanic ash and minerals that slowly replaced their organic material and turned them into dazzling quartz in shades of red, purple, and blue.
