Edmontosaurus regalis is a species of comb-crested hadrosaurid dinosaur. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian age of the Cretaceous Period 73 million years ago, but it may have possibly lived into the early Maastrichtian.
E. regalis was one of the largest hadrosaurids, measuring up to long and weighing around . It is classified as a genus of saurolophine (or hadrosaurine) hadrosaurid, a member of the group of hadrosaurids that lacked large, hollow crests, and instead had smaller, solid crests or fleshy combs. The distribution of E. regalis fossils suggests that it preferred coasts and coastal plains. It was a herbivore that could move on both two legs and four. Because it is known from several bone beds, E. regalis is thought to have lived in large groups. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, and its injuries and pathologies.
Edmontosaurus regalis is known from several fossil specimens. E. regalis was among the largest of hadrosaurids, as a fully grown adult could have been long. Some of the larger specimens reached the range of to long. Its weight was on the order of . The type specimen of E. regalis, NMC 2288, is estimated as long. A 2022 study proposed that E. regalis may have been heavier than its generic relative, E. annectens, but not enough samples exist to provide a valid estimate and examination on its osteohistology and growth, so the results for E. regalis aren't statistically significant.
The skull was roughly triangular in profile. One specimen preserved a soft tissue crest or wattle on top of its head. The beak was toothless, with both the upper and lower beaks being extended by keratinous material. Its teeth were present only in the maxillae (upper cheeks) and dentaries (main bone of the lower jaw). They grew in columns, with an observed maximum of six in each and the number of columns varied based on the animal's size.