Mix-up Peak, also known as Mixup Peak, is a mountain summit located on the shared boundary of Skagit County and Chelan County in Washington state. It is part of the North Cascades Range and is situated one mile south of Cascade Pass on the shared border of North Cascades National Park and Glacier Peak Wilderness. The nearest higher peak is Magic Mountain, to the east-southeast. Mix-up Peak is at the northern end of the Ptarmigan Traverse which is an alpine route to remote mountains such as Mount Formidable and Dome Peak. The Cache Glacier occupies a cirque below its eastern flank. Surface runoff on the east side the mountain drains into the Stehekin River, whereas precipitation runoff drains into the Cascade River from the west side.