History of Hawaii
Pearl Harbor was surprisingly attacked on December 7, 1941 by the Imperial Japanese Navy, killing 2,403 people and sinking the main American battleship fleet. Fortuitously, the four Pacific aircraft carriers were not in port and escaped damage. Hawaii was put under martial law until 1945. Unlike the West Coast of the United States in which 100,000 ethnic Japanese citizens were interned, the Japanese American population in Hawaii completely avoided such similar fate, though hundreds of pro-Japan leaders were arrested. Pearl Harbor was the U.S.' main forward base for the Pacific War. The Japanese tried to invade in summer 1942 but were defeated at the Battle of Midway. Hundreds of thousands of American soldiers, sailors, Marines, and airmen passed through on their way to the fighting.
United States Pacific Fleet
Subsequently Pacific Fleet engagements during World War II included the Battle of Guam, the Marshalls-Gilberts raids, the Doolittle Raid, the Solomon Islands campaign, the Battle of the Coral Sea, the Battle of Midway, the Battle of the Eastern Solomons, the Battle of the Santa Cruz Islands, the Battle of the Philippine Sea, the Gilbert and Marshall Islands campaign, the Battle of Leyte Gulf, and the Battle of Okinawa. More minor battles included the Battle of Dutch Harbor. The Submarine Force began a sustained campaign of commerce raiding against Japan's merchant marine, beginning the very first day of the war, which ultimately claimed 1,314 ships totalling about 5.3 million tons (by the imperfect postwar reckoning of the Joint Army-Navy Assessment Committee, JANAC). The West Loch disaster occurred at Pearl Harbor on 21 May 1944.