Iron Cap Mountain is a 6,347-foot (1,935-metre) mountain summit located two miles west-northwest of Dutch Miller Gap, in east King County of Washington state. It is situated in the heart of the Alpine Lakes Wilderness, on land managed by Mount Baker-Snoqualmie National Forest. Iron Cap Mountain is set two miles west of the crest of the Cascade Range. Precipitation runoff from the south side of the mountain drains into tributaries of the Snoqualmie River, whereas the north side drains into tributaries of the Foss River. Although modest in elevation, relief is significant since Iron Cap rises 2,500 feet above the Middle Fork Snoqalmie River Valley in less than one mile. Its neighbors include La Bohn Peak, 1.77 miles (2.85 km) to the east, and Little Big Chief Mountain, 2.14 miles (3.44 km) t