Dinosaur National Monument

Dinosaur National Monument
IUCN category III (natural monument or feature)
Multicolored beds of the Brushy Basin Member of the Morrison Formation near Carnegie Quarry
Location	Moffat County, Colorado / Uintah County, Utah, US
Nearest city	Vernal, Utah
Coordinates	40°32′N 108°59′W / 40.533°N 108.983°W / 40.533; -108.983Coordinates: 40°32′N 108°59′W / 40.533°N 108.983°W / 40.533; -108.983
Area	210,844 acres (853.26 km2)
Established	October 4, 1915
Visitors	360,584 (in 2005)
Governing body	U.S. National Park Service
Website	Dinosaur National Monument

Dinosaur National Monument is a U.S. National Monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument area is in Moffat County, Colorado, the Dinosaur Quarry 40°26′29″N 109°18′04″W / 40.44139°N 109.30111°W / 40.44139; -109.30111 is located in Utah just to the north of the town of Vernal, Utah.

The nearest communities are Vernal, Utah and Dinosaur, Colorado. This park contains over 800 paleontological sites and has fossils of dinosaurs including Allosaurus, Deinonychus, Abydosaurus (a nearly complete skull, lower jaws and first four neck vertebrae of the specimen DINO 16488 found here at the base of the Mussentuchit Member of the Cedar Mountain Formation is the holotype for the description) and various long-neck, long-tail sauropods. It was declared a National Monument on October 4, 1915.

The rock layer enclosing the fossils is a sandstone and conglomerate bed of alluvial or river bed origin known as the Morrison Formation from the Jurassic Period some 150 million years old. The dinosaurs and other ancient animals were carried by the river system which eventually entombed their remains.