In 1982, the only significant trees on the island were those planted by American soldiers at a chapel constructed after the 1943 battle when the Japanese occupation was over;[4] they have since gone.

Research of the large number of archaeological sites on the island suggests an estimated precontact population ranging from 2,000 to 5,000 Unangan (Aleut).

On June 7, 1942, six months after the Japanese attack on Pearl Harbor, the 301st Independent Infantry Battalion of the Japanese Northern Army landed on the island without opposition, one day after landing on nearby Kiska to the east, which made Attu the second of the only two invasion sites on territory belonging to the United States soil during the war.

[3] American authorities had previously evacuated about 880 Aleuts from villages elsewhere in the Aleutian Islands to the Alaska Panhandle,[citation needed] where about 75 of them died of various infectious diseases over two years.

Mrs. Jones, 63, was subsequently taken to the Bund Hotel in Yokohama, Japan, which also housed Australian prisoners of war from the 1942 Battle of Rabaul in Papua New Guinea.

No more reinforcements arrived after that time, owing mainly to the efforts of the U.S. naval force under Rear Admiral Charles "Soc" McMorris, and United States Navy submarines.

After the sizable naval Battle of the Komandorski Islands, the Japanese abandoned their attempts to resupply its Aleutian garrisons by surface ships.

A shortage of landing craft, unsuitable beaches, and equipment that failed to operate in the harsh weather caused great difficulties in projecting any force against the Japanese.

This led to bloody fighting: there were 3,929 U.S. casualties: 549 were killed, 1,148 were injured, 1,200 had severe cold injuries, 614 succumbed to infectious diseases, and 318 died of miscellaneous causes – largely from Japanese booby traps and from friendly fire.

The charge, led by Colonel Yamasaki, penetrated U.S. lines far enough to encounter shocked rear-echelon units of the American force.

U.S. burial teams counted 2,351 Japanese dead, but it was presumed that hundreds more had been buried by naval, air, and artillery bombardments over the course of the battle.

[4] On April 11, 1945, in a period of only two hours, at least nine Japanese incendiary balloons sent to start forest fires in the United States West Coast were intercepted and shot down near Attu by USAAF P-38 Lightning aircraft.

[15] The United States government decided to construct a LORAN station on the southern tip of Attu, at Theodore Point.

In 1987, with the approval of the U.S. Department of the Interior, the government of Japan placed a monument on Engineer Hill, site of the hand-to-hand finale of the battle against the Japanese.

[17] More remains were located at the burial site, but were left untouched with plans to return at a later time and have them exhumed properly.

On August 27, 2010, the station was decommissioned and the Coast Guard personnel left, leaving the island with no resident population.

[2] On June 7, 2012, the 70th anniversary of the Japanese invasion, Senator Lisa Murkowski and United States Coast Guard Rear Admiral Thomas Ostebo travelled to Attu and dedicated a memorial to Attu Village, its residents who died in Japanese captivity, and the survivors who were unable to return.

Due to the strong oceanic influence, Attu's climate is exceptionally mild for its latitude, with summers much cooler and winters much warmer than more continental locations.

Because it is so physically remote from other parts of North America, there are a number of bird species likely to be found on Attu that are not seen anywhere else on the continent.

[39] During his record-setting big year of 1998, in which he identified a record 745 species (later revised to 748), Sandy Komito spent 29 days (May 10 – June 7) on the island.

[clarification needed] Birding tours can still reach Attu, but only by a multi-day boat trip from Adak Island.

[42] Prior to World War II, the Bureau of Indian Affairs (BIA) operated the sole school on the island.

[43] A force consisting of 1,140 infantry under Major Matsutoshi Hosumi took control of the island and captured Attu's population, which consisted of 45 Aleuts and two white Americans, Charles Foster Jones (1879–1942), an amateur radio operator and weather reporter, originally from St. Paris, Ohio, and his wife Etta (1879–1965), a teacher and nurse, originally from Vineland, New Jersey.

[44] Charles Jones was killed by the Japanese forces immediately after the invasion because he refused to fix the radio he destroyed to prevent the occupying troops from using it.