The Kaiparowits Formation is a thick sedimentary rock unit on the Kaiparowits Plateau in southern Utah, laid down during the Late Cretaceous on river-crossed alluvial floodplains in coastal southern Laramidia. Sandstone preserves ancient river channels and mudstone preserves floodplain deposits. It is among the region’s richest fossil sources, preserving plants, fish, amphibians, turtles, crocodilians, pterosaurs, mammals, dinosaurs, and trace fossils. Finds from the formation have helped reconstruct a lush ecosystem near the Western Interior Seaway and have contributed to debates about dinosaur evolution and regional isolation on Laramidia. Much of its fossil record remains unexplored.