Since 2000, numerous dinosaur fossils over 75 million years old have been found at Grand Staircase–Escalante.

In 2002, a volunteer at the monument discovered a 75-million-year-old dinosaur near the Arizona border.
On October 3, 2007, the dinosaur's name, Gryposaurus monumentensis (hook-beaked lizard from the monument) was announced in the Zoological Journal of the Linnean Society.
G. monumentensis was at least 30 feet (9.1 m) long and 10 feet (3.0 m) tall, and has a powerful jaw with more than 800 teeth.
Many of the specimens from the Kaiparowits Formation are reposited at the Natural History Museum of Utah in Salt Lake City.

Two ceratopsid (horned) dinosaurs, also discovered at the monument, were introduced by the Utah Geological Survey in 2007.
They were uncovered in the Wahweap formation, which is just below the Kaiparowits formation where the duckbill was extracted.
They lived about 80 million or 81 million years ago.
The two fossils are called the Last Chance skull and the Nipple Butte skull.
They were found in 2002 and 2001, respectively.
Both were later identified as belonging to Diabloceratops.

In 2013 the discovery of a new species, Lythronax argestes, was announced.
It is a tyrannosaur that is approximately 13 million years older than Tyrannosaurus, named for its great resemblance to its descendant.
The specimen can be seen at the Natural History Museum of Utah.
Since 2000, numerous dinosaur fossils over 75 million years old have been found at Grand Staircase–Escalante.
In 2002, a volunteer at the monument discovered a 75-million-year-old dinosaur near the Arizona border. On October 3, 2007, the dinosaur's name, Gryposaurus monumentensis (hook-beaked lizard from the monument) was announced in the Zoological Journal of the Linnean Society. G. monumentensis was at least 30 feet (9.1 m) long and 10 feet (3.0 m) tall, and has a powerful jaw with more than 800 teeth. Many of the specimens from the Kaiparowits Formation are reposited at the Natural History Museum of Utah in Salt Lake City.
Two ceratopsid (horned) dinosaurs, also discovered at the monument, were introduced by the Utah Geological Survey in 2007. They were uncovered in the Wahweap formation, which is just below the Kaiparowits formation where the duckbill was extracted. They lived about 80 million or 81 million years ago. The two fossils are called the Last Chance skull and the Nipple Butte skull. They were found in 2002 and 2001, respectively. Both were later identified as belonging to Diabloceratops.
In 2013 the discovery of a new species, Lythronax argestes, was announced. It is a tyrannosaur that is approximately 13 million years older than Tyrannosaurus, named for its great resemblance to its descendant. The specimen can be seen at the Natural History Museum of Utah.
Grand Staircase–Escalante National Monument