Cape Field at Fort Glenn, Military historic district in Umnak Island, Alaska

Cape Field at Fort Glenn is a World War II military airfield on Umnak Island, featuring four runways made of pierced steel planking and numerous barracks, ammunition storage buildings, and artillery positions. The structures are spread across the terrain in varying states of preservation.

The base was rapidly built in 1942 following the Pearl Harbor attack to defend Alaska, constructed in secret under the cover story of a cannery. It became central to defending against Japanese operations in the region during the war.

Construction crews worked around the clock in three shifts, and Morrison-Knudsen built hundreds of Quonset huts to replace tents exposed to sudden island storms. The base housed 119 officers and 359 men, with a Kodiak-type hangar, a 160 by 90 foot structure, and a small eight-bed hospital. The name Fort Glenn honored the site's first commander.

The site is remote on an Aleutian island and can be difficult to access, requiring careful planning and preparation for any visit. Visitors should be prepared for harsh weather, uneven terrain, and limited on-site infrastructure.

On 3 June 1942 Japanese carrier aircraft struck Dutch Harbor on Amaknak Island. P-40 Warhawks of the 11th Fighter Squadron, based at Fort Glenn, rose with naval fighters to meet them; the Japanese lost two A6M Zeroes, possibly a third to ground fire, plus Val dive bombers and a Dave reconnaissance seaplane. B-26 Marauders of the 77th Bombardment Squadron, sent to find the carriers, landed at Fort Glenn around 1:30 pm because of fog.