Mount Washington is a deeply eroded volcano in Oregon’s Cascade Range, notable for its narrow, spire-like profile and stark setting between North Sister and Three Fingered Jack. Formed in the late Pleistocene by subduction of the Juan de Fuca Plate beneath the North American Plate, it combines features of shield volcanoes and stratovolcanoes and has been heavily carved by glaciation. The surrounding Mount Washington Wilderness preserves lava fields, cinder cones, moraines, lakes, and austere volcanic terrain shaped by eruptions in the region as recently as about 1,350 years ago. Lightly used by people, the area is valued chiefly for its raw scenery, geology, and protected wilderness character.