Whitehorse Mountain is a peak near the western edge of the North Cascades in Washington state. It is located just southwest of the Sauk River Valley town of Darrington, near the northern boundary of Boulder River Wilderness in Mount Baker-Snoqualmie National Forest. While not of particularly high absolute elevation, even for the North Cascades, it is notable for its large, steep local relief. For example, its north face rises 6,000 feet in only 1.8 mi (2.9 km).

The North Cascades are a section of the Cascade Range of western North America. They span the border between the Canadian province of British Columbia and the U.S. state of Washington and are officially named in the U.S. and Canada as the Cascade Mountains. The portion in Canada is known to Americans as the Canadian Cascades, a designation that also includes the mountains above the east bank of the Fraser Canyon as far north as the town of Lytton, at the confluence of the Thompson and Fraser Rivers.