Castle Peak is a remote 8,343-foot summit in Washington’s North Cascades, on the Cascade crest in the Pasayten Wilderness near the Canada–United States border. The second-highest peak in the Hozameen Range and the sixth-highest in the wilderness, it is known for especially rugged terrain, rising nearly 3,000 feet above Crow Creek in less than a mile. Its slopes drain both east toward the Similkameen River system and west toward the Skagit, marking a divide between wetter and drier climates. Shaped by tectonic activity, uplift, faulting, and repeated Pleistocene glaciation, the mountain also attracts climbers with routes from scrambles to technical ascents.