Although specialists in Washington had decoded a Japanese message indicating that an attack in the Pacific was imminent, atmospheric difficulties and human error kept the message from being delivered in time. As it became apparent that O‘ahu would be caught off guard, the commander of the Japanese squadron signaled the attack to begin. Despite their short-run victory, Japan went on to lose the war.
The loss of life in the attack was substantial, but not all of Japan's objectives had been met. All but three of the 18 warships damaged during the raid—the Arizona, Utah and Oklahoma—were repaired and returned to duty. The fleet's three aircraft carriers, away from Pearl Harbor during the attack, were undamaged. The oil-storage tanks, a prime Japanese target, were not destroyed. Pearl Harbor survived and continued to function as a Pacific base of naval operations throughout the war.
The value of the harbor, which is the double estuary of the Pearl River, was recognized in 1840 by U.S. Navy Lt. Charles Wilkes. He discovered that dredging an outlying reef would make Pearl Harbor readily accessible. About 30 years later U.S. Army Col. John M. Schofield recommended that the United States secure harbor rights. This was done in 1873; work began in 1898.
Pearl Harbor has grown dramatically in value and covers more than 10,000 acres of land. Most of the United States Navy commands in the Pacific have headquarters at Pearl Harbor. A naval shipyard, supply center and submarine base are among the harbor's various facilities.
The Pearl Harbor National Memorial (formerly called the World War II Valor in the Pacific National Monument), established by presidential proclamation in 2008, consists of nine historic sites in Pearl Harbor, Alaska's Aleutian Islands and California. Among the five Pearl Harbor sites are the USS Arizona Memorial , the USS Utah Memorial and the USS Oklahoma Memorial.
The USS Utah Memorial is on Ford Island, about three-quarters of a mile east of the USS Arizona Memorial, and is accessible to civilians with a military sponsor. The USS Oklahoma Memorial, also on Ford Island, stands near the entrance to the Battleship Missouri Memorial and may be visited after a tour of the Missouri.