Merycoidodon ("ruminating teeth") is an extinct genus of terrestrial herbivore of the family Merycoidodontidae, subfamily Merycoidodontinae (oreodont), more popularly known by the name Oreodon ("hillock teeth") endemic to North America during the Late Eocene-Early Miocene subepochs (38—16.3 mya) existing for approximately 21.7 million years.