Steens Mountain is a massive isolated fault-block mountain in southeastern Oregon, the state’s largest of its kind, rising sharply from the Alvord Desert to nearly 9,738 feet. Formed as a horst of flood basalt laid down 17 to 14 million years ago, it was later shaped by cracking, erosion, landslides, ice, and snowmelt. Its elevation zones support varied plant and animal life, including endemic species, while notably lacking expected pine-family trees. Native Americans long used the area, and in 1860 it was renamed for Major Enoch Steen after U.S. Army campaigns against Paiute people. Much of the mountain is now protected and widely used for recreation.