A peninsula of south-central to southwest Alaska. It is a continuation of the Aleutian Range between the Bering Sea and the Pacific Ocean. Peninsula, southwestern Alaska, U.S. It stretches about 500 mi (800 km) between the Pacific Ocean and Bristol Bay. The volcanic Aleutian Range runs along its entire length. It is the site of Katmai National Park and Preserve, Aniakchak National Monument and Preserve, and the Becherof, Alaska Peninsula, and Izembek national wildlife refuges