Mule Deer habitat is in the western half of North America. It gets its name from its large mule-like ears. Adult males are called bucks, adult females are called does, and young of both sexes are called fawns. Unlike its cousin, White-tailed, mule deer are generally more associated with the land west of the Missouri River. The most noticeable differences between whitetails and mule deer are the color of their tails and configuration of their antlers. The mule deer's tail is black tipped. Mule deer antlers are bifurcated, or "fork" as they grow rather than branching from a single main beam (as with white-tails). Each year a buck's antlers start to grow in spring and are shed after mating season from mid-January to mid-April. Mule deer bucks have somewhat more prominent ears than females. Instead of running, mule deer move with a bounding leap, stot, with all four feet coming down together.[ The mule deer is the largest of the Odocoileus genus, standing, on the average, 40 to 42 inches at the shoulders and stretching 80 inches or so nose to tail. An adult buck will weigh from 150 to 300 pounds on the hoof, with does averaging 125 to 175 pounds. The occasional trophy-sized mule deer buck may weigh in around 500 pounds. The Mule Deer does not show marked size variation across its range as does the White-tailed Deer.

The species is common in the Inter Mountain West where it can be found in many types of habitat, ranging from open deserts to high mountain and urban areas.