The
Island Park Caldera in the states of
Idaho and
Wyoming,
U.S., is one of the world's largest
calderas, with approximate dimensions of 80 by 65 km. Its
ashfall is the source of the
Huckleberry Ridge Tuff that is found from southern California to the Mississippi River near St. Louis. This super-eruption of approximately occurred 2.1 (million years ago) and produced 2,500 times as much ash as the
1980 Mount St. Helens eruption. Island Park Caldera has the smaller and younger
Henry's Fork Caldera nested inside it.