view of surprise lake from the rim of the aniakchak crater

Surprise Lake from the rim of Aniakchak Crater. NPS Photo

Quick Facts

Location:
Aniakchak National Monument, Alaska
Significance:
One of the largest explosive craters in the world.
Designation:
National Natural Landmark
OPEN TO PUBLIC:
Yes
Aniakchak Crater, located within Aniakchak National Monument, is one of the largest explosive craters in the world, averaging 6 miles wide and 2000 feet deep. The crater contains Surprise Lake, a warm springs fed lake that provides spawning grounds for a unique subspecies of salmon. The lake is the source of the Aniakchak River, which flows through a breach in the crater rim to the Pacific Ocean. The last eruption of this volcano was in 1931. It was designated in 1967, and is comprised of 20,727 acres.