Alaska Peninsula, a long, narrow tongue of land in Alaska. From Iliamna Lake the peninsula stretches generally south-westward for about 500 miles (800 km) almost to Unimak Island in the Aleutian chain. The waters of the Pacific Ocean wash the deeply indented and island-studded southern coast; the Bering Sea borders the more regular northern coast.

The Alaska Peninsula is largely a cold, barren region with few trees and shrubs. The rugged, desolate Aleutian Range runs the length of the peninsula. Numerous volcanoes dot the range. In Katmai National Park and Preserve are thousands of steaming fissures, the most notable of which are in the Valley of Ten Thousand Smokes. Veniaminof Volcano, 8,225 feet (2,507 m) above sea level, is the loftiest peak.

People on the sparsely populated peninsula—mainly Aleuts—live in small coastal villages. Hunting and fishing in the region's wilderness attract tourists.