The Corythosaurus is a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 77-76.5 million years ago. It lived in what is now North America. Its name means "helmet lizard", from the Greek korythos meaning "helmet" and sauros meaning "lizard", because the crest shape resembled a Corinthian soldier's helmet.

The first specimen was discovered in 1912 by Barnum Brown in Red Deer River, Alberta, Canada. As well as an almost complete skeleton, the find was remarkable because much of the creature's fossilized skin had also survived. In 1916, the Canadian (Canadian Pacific Lines) ship Mount Temple was carrying two specimens and other fossils from today's Dinosaur Provincial Park, Alberta, Canada to Britain. It was sunk by the German surface raider SMS Möwe, sending its 75 million year old cargo to the bottom of the North Atlantic, where it rests to this day.