Apex Mountain is an 8,302-foot summit in northern Washington’s Okanogan Range, within the Pasayten Wilderness near the Canada–United States border. On the east side of the Cascade crest, it rises sharply above surrounding terrain, especially near Tungsten Lake, and stands near Apex Pass, where the Pacific Northwest Trail crosses its northern slopes. Its waters drain west to Cathedral Creek and east to Tungsten Creek, both within the Chewuch River system. The mountain lies in the North Cascades’ climatic transition zone, shaped by Pacific weather and snowy winters, and in a landscape formed over millions of years by tectonic activity, uplift, faulting, and repeated glaciation.