The Hagerman Fossil Beds are a significant paleontological site located in Idaho, USA. This area is known for its rich deposits of fossils from the late Pliocene epoch, approximately 3.5 million years ago. The site has yielded a variety of fossils, including those of the extinct Hagerman horse, which is one of the earliest known horses in North America. Designated as a National Monument in 1988, the Hagerman Fossil Beds preserve a unique ecosystem that once thrived in the region. The fossil beds provide valuable insights into the climate and environment of the time, as well as the diverse species that inhabited the area, including mastodons and giant ground sloths.