Pearl Harbor

Pearl Harbor is a lagoon harbor on the island of Oʻahu, Hawaii, United States, west of Honolulu. It was often visited by the naval fleet of the United States before it was acquired from the Hawaiian Kingdom by the U.S. with the signing of the Reciprocity Treaty of 1875. Much of the harbor and surrounding lands are now a United States Navy deep-water naval base. It is also the headquarters of the United States Pacific Fleet. The U.S. government first obtained exclusive use of the inlet and the right to maintain a repair and coaling station for ships here in 1887. The surprise attack on the harbor by the Imperial Japanese Navy on December 7, 1941, led the United States to declare war on the Empire of Japan, marking the United States' entry into World War II.