Mix-up Peak is a 7,440-foot mountain in Washington’s North Cascades on the boundary of Skagit and Chelan counties, just south of Cascade Pass where North Cascades National Park meets the Glacier Peak Wilderness. It is notable as the northern end of the Ptarmigan Traverse, an alpine route linking remote peaks such as Mount Formidable and Dome Peak. Cache Glacier lies in a cirque on its eastern side, while runoff drains east to the Stehekin River system and west toward the Cascade River. The mountain stands in terrain formed by long volcanic, tectonic, and Pleistocene glacial processes, within a wet marine west coast climate.