Fort Glenn was a World War II military base on the northeast coast of Umnak Island in the Eastern Aleutians, about 67 miles (108 km) southwest of Dutch Harbor and 49 miles (79 km) northeast of Nikolski, Alaska. The base was named in 1942 by the U.S. Army for Brigadier General E.F. Glenn, and the name was first published on topographic maps in 1947 by the U.S. Geological Survey.

Fort Glenn was built during the secret military buildup of the Territory of Alaska that began in 1941 in anticipation of an attack by Japanese forces during the Aleutian Island campaign. In March 1942, U.S. Army personnel with the 807th Army Engineers disguised as civilian employees of the Blair Canning and Packing Company started working on the airfields on Umnak Island and Cold Bay. The base on Umnak Island eventually consisted of Fort Glenn Army Air Base, an airfield of the U.S. Army Air Corps later renamed Cape Air Force Base, the adjacent Otter Point Naval Air Facility, and a U.S Navy base at Chernofski Harbor, 12 miles (19 km) to the east on Unalaska Island which was the main supply port for Fort Glenn. Fort Glenn had about 10,000 personnel by the end of 1942, and the facilities eventually included hundreds of Quonset huts, storage buildings, ammunition magazines, aircraft hangars, administration offices, radio and radar facilities, and 4 aircraft runways.

Newer air bases on Adak and Amchitka Islands further west quickly supplanted Fort Glenn as a forward operating base. By the end of 1943, the base mission had become to provide support for transient personnel and aircraft, and the site was deactivated in 1947. Today hundreds of building pits, the runways, and World War II artillery emplacements remain in various states of deterioration. Fort Glenn was listed on the National Register of Historic Places and declared a National Historic Landmark in 1987. Read more here and here. Explore more of Fort Glenn and Umnak Island here: