Castoroides is a genus of very large beaver in the subfamily Castoroidinae. Its remains are found in North America. This animal originally lived between three million and 11,000 years ago, from the Piacenzian age of the Neogene period to the Meghalayan age of the Quaternary. There are two species: Castoroides dilophidus inhabited the southeastern part of its range, while Castoroides ohioensis lived throughout the rest of its habitat.
