Also known as wapiti, this relative of the European red deer was once one of the most common American species of deer. After the extinction of the eastern population, its range is largely constricted to the U.S west of the Rockies, save for the reintroduced populations in various eastern states.

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Once divided into numerous subspecies – the Tule in California, Merriam's in the Southwest, Roosevelt in the Pacific Northwest, Manitoban in the Canadian prairies and Midwest, Eastern on the east coast, and the Rocky Mountains subspecies in the Rockies – recent DNA studies suggest there are only 3 American subspecies. Aside from the Roosevelt and Tule, which seem to be genetically autonomous, all other American subspecies appear to be only 1 subspecies. This would mean that the Merriam's and Eastern subspecies, long considered extinct, are just extirpated populations genetically identical to the Rocky Mountain's subspecies, which have already been reintroduced to their former habitats.