Iron Mountain, Mountain summit in Pierce County, United States.

Iron Mountain is a 6,286-foot (1,916 m) summit in Mount Rainier National Park, Pierce County, Washington, near the base of the Success Cleaver above Indian Henry's Hunting Ground. Its top is bare grey rock with vertical cracks and ledges; below, steep slopes mix grey scree, low brown and green vegetation and scattered small dark trees, with dense conifer forest on the lower flanks.

The peak was officially named by the United States Board on Geographic Names in 1932 following local mining interest in the area. The naming reflects early human interest in the mountain's resources.

The name comes from dark reddish rock that late-1800s prospectors took for iron or iron oxide, part of hopes that Mount Rainier mines would yield copper, silver and gold. The United States Board on Geographic Names adopted the toponym officially in 1932.

Iron Mountain sits near the base of the Success Cleaver, overlooking Indian Henry's Hunting Ground, with Copper Mountain 0.3 miles (0.48 km) to the north as the nearest higher neighbour. Snow on the west side of the Cascades is wet and heavy, so avalanche danger is high in winter; summer often brings little or no cloud cover. Runoff drains into Tahoma Creek, Devils Dream Creek and Fishers Horn Pipe Creek.

The dark reddish rock on Iron Mountain was once mistaken for iron ore, prompting hopes in the late 1800s that Mount Rainier's slopes held copper, silver and gold. The summit was officially named in 1932 by the United States Board of Geographic Names. Its runoff drains into Tahoma Creek, Devils Dream Creek and Fishers Horn Pipe Creek.