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
In December 1941, the fleet consisted of nine battleships, three aircraft carriers, 12 heavy cruisers, eight light cruisers, 50 destroyers, 33 submarines, and 100 patrol bombers. This was approximately the fleet's strength at the time of the Japanese attack on Pearl Harbor. That day, the Japanese Combined Fleet carried out the attack on Pearl Harbor, drawing the United States into World War II in the Pacific. The Pacific Fleet's Battle Line took the brunt of the attack, with two battleships destroyed, two salvageable but requiring lengthy reconstruction, and four more lightly to moderately damaged, forcing the U.S. Navy to rely primarily on aircraft carriers and submarines for many months afterward.