The island of Guam in the western Pacific was one of several U.S. territories occupied by the Japanese during World War II, others notably being the Philippines and a portion of Alaska.
The United States acquired Guam and the Philippines from Spain in 1898, following the Spanish-American War.
The first battle of Guam took place Dec. 8-10, 1941. The island was defended by a small, lightly armed garrison of sailors and Marines. They were quickly overrun by the larger Japanese landing force.
The United States didn't have time to sufficiently mobilize its fleet and resources, as the island fell just a week after the Japanese surprise attack on Pearl Harbor on Dec. 7. The U.S. was much more prepared by the time of the second battle, which took place July 21 to Aug. 10, 1944.
The second battle of Guam was part of a larger island campaign known as Operation Forager, which included Guam and the rest of the Mariana Islands, as well as the Palau island group.
The invasion of the 212-square-mile island of Guam was made by Marines from the 3rd Marine Amphibious Corps, supported by naval landing craft and naval gunfire and airstrikes. The Army's 77th Infantry Division also conducted a landing and participated in the battle.
Coast Guard cutters also participated in the battle, making it a truly joint operation with every military service present.
Around 59,000 U.S. service members and a large number of native Chamorros faced about 18,000 Japanese. Fighting in the thick jungle and steep terrain was difficult for both sides, with about 3,000 U.S. troops killed and more than 18,000 Japanese dead when it was over.
Although organized Japanese resistance ended Aug. 10, some 7,500 Japanese soldiers remained in the jungle for some time, and some continued the fight. The last of the Japanese soldiers, Shoichi Yokoi, was discovered Jan. 24, 1972.
A few months following liberation, Navy Adm. Chester Nimitz, the commander in chief of Pacific Ocean Areas, established the island as his headquarters for the remainder of the war. The strategic location of Guam and the rest of the Mariana Islands, of which Guam is part, allowed American land-based bomber crews, for the first time, to make round-trip strikes directly at the Japanese home islands.
Today, Guam remains a strategic U.S. territory, with the location of Joint Region Marianas, a joint military command that combined the bases formerly known as Andersen Air Force Base and Naval Base Guam. Coast Guard cutters are also stationed there.
July 21st is celebrated as Guam Liberation Day, the day when Americans came ashore in 1944. Alaska's Aleutian Islands were liberated in 1943, and the Philippines would be liberated by the early part of 1945. The Japanese formally surrendered Sept. 2, 1945.