John Day Fossil Beds National Monument is a
U.S. National Monument in
Wheeler and
Grant counties in east-central
Oregon. Located within the
John Day River basin and managed by the
National Park Service, the park is known for its well-preserved layers of
fossil plants and
mammals that lived in the region between the late
Eocene, about 45 million years ago, and the late
Miocene, about 5 million years ago. The monument consists of three geographically separate units: Sheep Rock, Painted Hills, and Clarno.