The Steens Mountain Wilderness is a wilderness area surrounding a portion of Steens Mountain of southeastern Oregon in the United States. The reserve falls within the Steens Mountain Cooperative Management and Protection Area (CMPA). Both the reserve and the CMPA are administered by the Bureau of Land Management. The wilderness area encompasses 170,166 acres (68,864ha) of the CMPA's total 428,156 acres (173,269ha).[3]98,859 acres (40,007ha) of the Wilderness are protected from grazing and free of cattle.[4]
Steens Mountain is the largest fault-block mountain in North America. Pressure under the Earth's surface thrust the block upward approximately 20million years ago, resulting in a steep eastern face with a more gentle slope on the western side of the mountain. During the Ice Age, glaciers carved several deep gorges into the peak and created depressions where Lily, Fish, and Wildhorse lakes now stand.[5]