Surprise Lake

A hiker on a hill above a lake with a float plane
Surprise Lake is the headwaters for Aniakchak River.

Photo courtesy L. Law

Quick Facts

Scenic View/Photo Spot

Aniakchak Caldera was once partly filled with a large lake, similar to Crater Lake in Oregon. Eventually, a weaker portion of the caldera rim collapsed. The resulting outflow eroded the rim to create The Gates through which the Aniakchak River now flows. Surprise Lake, located in the northeast part of the caldera, is all that remains of the once larger lake. Warm springs, melting snow, and glaciers feed Surprise Lake, which in turn gives rise to the Aniakchak River.

Aniakchak National Monument & Preserve

Last updated: April 2, 2021