Holliway Mountain is a granite summit of more than 8,000 feet in the Okanogan Range of Washington’s North Cascades, near the headwaters of the Methow River on Okanogan–Wenatchee National Forest land. It is part of the Golden Horn Batholith, one of many granite peaks around Washington Pass tied to the region’s long geologic development. The North Cascades took shape through tectonic uplift, volcanic activity, and the accretion of terranes about 50 million years ago, then were deeply sculpted by repeated Pleistocene glaciation into steep terrain and U-shaped valleys. The mountain also lies in a marine west coast climate that brings heavy winter snowfall and generally clearer summers.