Steens Mountain Wilderness is a protected high-desert landscape in southeastern Oregon within the larger Steens Mountain Cooperative Management and Protection Area, administered by the Bureau of Land Management. Encompassing much of Steens Mountain, it rises from about 4,200 feet to 9,733 feet and includes the largest fault-block mountain in North America, shaped by uplift about 20 million years ago and later carved by Ice Age glaciers into deep gorges and lake basins. Its habitats shift sharply with elevation, from sagebrush near the Alvord Desert to juniper, aspen, meadows, and snow zone, supporting endemic plants and diverse wildlife including bighorn sheep, elk, pronghorn, redband trout, and mustangs.