Many people are surprised to learn that Ohio is a good place to see and collect fossils. Ohio rocks do not have dinosaur fossils, but they do contain fossils from both marine (sea) and terrestrial (land) environments. The fossils occur in rocks that were deposited hundreds of millions of years ago, during the Paleozoic Era, long before the first dinosaurs.
In addition to these ancient fossils, Ohio has more recent fossils from the last Ice Age, which began a few million years ago and ended only 11,700 years ago. At times during Ohio's Ice Age, two thirds of the state was covered by immense ice sheets that were up to a mile thick in northern Ohio. Large mammals, such as wooly mammoths, mastodons, giant ground sloths, and giant beavers lived in Ohio at this time.
Fossils are found in every county in the state, but southwestern Ohio is known around the world for its well-preserved marine fossils. Rocks exposed here were deposited about 450 million years ago, during the Ordovician Period, when Ohio was covered by a shallow sea. Fossil shells of invertebrate animals, such as brachiopods, corals, and crinoids, are abundant. Ohio's official State Invertebrate Fossil, the large trilobite Isotelus, is found in this part of the state.
Ohioans can discover (and at some locations collect) fossils at several state and local parks. To begin searching for fossils in Ohio, check out the resources below, which include downloadable brochures on Ohio's fossils, a series of webinars on fossils and fossil hunting in Ohio, and a list of state parks where fossils can be viewed and even collected at a few locations (a permit may be required).
Visit the ODNR YouTube page to view the Ohio Rock Talks series on Ohio fossils and fossil collecting.
- GeoFacts 5: Ohio Trilobites
- GeoFacts 6: Isotelus: Ohio's State Fossil
- GeoFacts 17: Fossil Collecting in Ohio
- GeoFacts 24: Tiny Hidden Treasures—The Microfossils of Ohio
Learn more about fossil collecting in Ohio from the ODNR Division of Geological Survey.