Alsek Glacier, glacier in the United States

Alsek Glacier is a 24-kilometer (15 mi) glacier in Glacier Bay National Park in Alaska's Panhandle. Its feeding area lies northwest of Mount Hay on the west flank of the Fairweather Range at 1,200 m. The 1.2-km-wide glacier flows west into Alsek Lake, which feeds the Alsek River.

The glacier was named in 1901 by U.S. Navy Lieutenant Commander Moser, commander of the Bureau of Fisheries steamer USS Albatross. In the 20th century it retreated about 3.5 km, and its ice front split on a rock into two tongues. Over the same period, the area of Alsek Lake doubled.

The name Alsek comes from the Tlingit language and may mean "place where people rest". The glacier and surrounding landscape have been part of the world of the Tlingit and other Native peoples for generations.

The glacier is remote and best viewed from the water by boat or from the air by small flight. Visitors should bring warm clothing and supplies, travel with experienced guides who know the terrain, and plan visits for summer when days are longest and weather is most stable.

The glacier's retreat of about 3.5 km in the 20th century split its ice front on a rock into two tongues, and Alsek Lake doubled in area over the same period. The lake now forms the glacier's edge and drains into the Alsek River.