Mount Mageik is a stratovolcano on the Alaska Peninsula. It has no confirmed historical eruptions (one in 1946 is now deemed questionable), but its youngest eruptive products are apparently Holocene in age (8750 to 500 BCE). A young crater lies on the northeast flank of the central summit cone, and is the site of vigorous superheated fumarolic activity with prominent sulfur deposits. The volcanic cones are composed of andesite, basaltic andesite and dacite.