Castle Peak, Mountain summit in Idaho, United States.

Castle Peak rises to 11,815 feet (3,600 meters) in the White Cloud Mountains of Idaho and features steep rock faces with extensive talus fields along its ridges. The summit area presents a complex terrain with sharp ridgelines and dramatic elevation changes typical of high alpine environments.

A proposed open-pit molybdenum mine at the base of Castle Peak became a leading issue in the 1970 Idaho gubernatorial race. In a rematch of 1966, Cecil Andrus defeated incumbent Don Samuelson, becoming the state's first Democratic governor in nearly a quarter-century. The dispute advanced the formation of the Sawtooth National Recreation Area in 1972, which includes the peak within the Cecil D. Andrus–White Clouds Wilderness.

The name Castle Peak comes from the summit's castle-like rock towers, visible from Castle Lake below. The easiest route is a class 3 scramble from Chamberlain Basin, and no trail reaches the top; trails from the parking area only approach the peak. Camping is allowed anywhere in Sawtooth National Forest, and the surrounding lakes serve as base camps.

Visitors need advanced mountaineering skills and proper alpine equipment for the technical routes found here. Weather conditions change rapidly at this elevation, so careful planning and preparation are essential before attempting an ascent.

Despite standing below the 12,000-foot mark, this peak has a prominence of approximately 4,035 feet, making it rank among Idaho's most important summits. This characteristic makes it far more interesting to climbers than many taller neighboring peaks.