They contain more than 75 volcanoes, about half of which are know to have erupted during the last 200 years. Not much of the land on the islands or on the peninsula is level.
Steep slopes prevail all the way to water's edge, and shores are rocky and craggy.
The Alaska Peninsula has intensely glaciated mountains indented with fjords that are bordered by cliffs. Several large lakes are on the peninsula. Treeless slopes along the Pacific coast of the Alaska Peninsula, Aniakchak National Monument. The climate is characterized by fog and rain, with the amount of precipitation varying little from month to month. In general, smaller islands receive less precipitation than larger islands.