Battle of Attu The Battle of Attu , which took place from May 11 – 30 , 1943 , was fought entirely between forces of the United States and the Empire of Japan on Attu Island off the coast of Alaska . The action , which was part of the Aleutian Islands Campaign during the Pacific War , was the only land battle of World War II fought on territory that was part of the incorporated territory of the U . S . It is also the only land battle in which Japanese and American forces fought in Arctic conditions . The battle , which lasted for more than two weeks , ended when most of the Japanese defenders were killed in brutal hand - to - hand combat after a final " banzai " charge broke through American lines . Background . The strategic position of the islands of Attu and Kiska meant their location could control the sea lanes across the Northern Pacific Ocean . Japanese planners believed control of the Aleutians would therefore prevent any possible U . S . attacks from Alaska . This assessment had already been inferred by U . S . General Billy Mitchell who told the U . S . Congress in 1935 , " I believe that in the future , whoever holds Alaska will hold the world . I think it is the most important strategic place in the world . " On June 7 , 1942 , six months after the United States entered World War II , the 301st Independent Infantry Battalion from the Japanese Northern Army landed unopposed on Attu . The landings occurred one day after the invasion of nearby Kiska . The U . S military now feared both islands could be turned into strategic Japanese airbases from which aerial attacks could be launched against the West Coast of North America . In Walt Disney ′ s 1943 film " Victory Through Air Power , " the use of the Aleutian Islands for American long - range bombers to bomb Japan from American territory was postulated . Recapture . In May 1943 , units from 17th Infantry , of the U . S . 7th Infantry Division made amphibious landings on Attu to retake the island from Japanese Imperial Army forces led by Colonel Yasuyo Yamasaki . Despite heavy naval bombardments of Japanese positions , the American troops encountered strong entrenched defenses that made combat conditions tough . Arctic weather conditions and also caused numerous casualties among U . S . forces . But after two weeks of relentless fighting , American units managed to push the Japanese defenders back to a pocket around Chichagof Harbor . On May 29 , without hope of rescue , Yamasaki led his remaining troops in a " banzai " charge . The momentum of the surprise attack broke through the American front line positions . Shocked American rear - echelon troops were soon fighting hand - to - hand combat with Japanese soldiers . The battle continued until almost all of the Japanese were killed . The charge effectively ended the battle for the island , although U . S . Navy reports indicate that small groups of Japanese continued to fight until early July . In 19 days of battle , 549 soldiers of the 7th Division were killed and more than 1 , 000 injured . The Japanese lost over 2 , 850 men ; only 29 prisoners were taken alive . Aftermath . Attu was to be the last action of the Aleutian campaign . The Japanese Northern Army secretly evacuated their remaining garrison from nearby Kiska , ending the Japanese occupation in the Aleutian Islands on July 28 , 1943 . The loss of Attu and the evacuation of Kiska came shortly after the death of Admiral Isoroku Yamamoto , who was killed by an American plane in Operation Vengeance . These defeats compounded the demoralizing effect of losing Yamamoto on the Japanese High Command . Despite the losses , Japanese propaganda attempted to present the Aleutian Island campaign as an inspirational epic .