Pearl Harbor is a lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. Much of the harbor and surrounding lands is a United States Navy deep-water naval base. It is also the headquarters of the United States Pacific Fleet. The attack on Pearl Harbor by the Empire of Japan on Sunday, December 7, 1941 brought the United States into World War II.
Pearl Harbor was originally an extensive deep embayment called Wai Nomi (meaning, “pearl water”) or Puʻuloa (meaning, “long hill”) by the Hawaiians. Puʻuloa was regarded as the neighbor of the dolphin god, Kaʻahupahau, and his brother (or father), Kahiʻuka, in Hawaiian legends. According to tradition, Keaunui, the head of the powerful Ewu chiefs, is credited with cutting a navigable channel near the present Puʻuloa saltworks, by which he made the estuary, known as "Pearl Lake," accessible to navigation. Making due allowance for legendary amplification, the estuary already had an outlet for its waters where the present gap is; but Keaunui is typically given the credit for widening and deepening it.
During the early 19th century, Pearl Harbor was not used for large ships due to its shallow entrance. The interest of United States in the Hawaiian Islands followed its whaling and trading ships in the Pacific. As early as 1820, an "Agent of the United States for Commerce and Seamen" was appointed to look after American business in the Port of Honolulu. These commercial ties to the American continent were accompanied by the work of the American Board of Commissioners for Foreign Missions. American missionaries and their families became an integral part of the Hawaiian political body.
Throughout the 1820s and 1830s, many American warships visited Honolulu. In most cases, the commanding officers carried letters from the U.S. Government giving advice on governmental affairs and of the relations of the island nation with foreign powers. In 1841, the newspaper Polynesian, printed in Honolulu, advocated that the U.S. establish a naval base in Hawaii for protection of American citizens engaged in the whaling industry. The British Hawaiian Minister of Foreign Affairs Robert Crichton Wyllie, remarked in 1840 that "...my opinion is that the tide of events rushes on to annexation to the United States."
With the conclusion of the Civil War, the purchase of Alaska, the increased importance of the Pacific states, the projected trade with the Orient and the desire for a duty free market for Hawaiian staples, Hawaiian trade expanded. In 1865, the North Pacific Squadron was formed to embrace the western coast and Hawaii. Lackawanna in the following year was assigned to cruise among the islands, "a locality of great and increasing interest and importance." This vessel surveyed the Northwestern Hawaiian Islands toward Japan. As a result the United States claimed Midway Island. The Secretary of the Navy was able to write in his annual report of 1868, that in November 1867, 42 American flags flew over whaleships and merchant vessels in Honolulu to only six of other nations. This increased activity caused the permanent assignment of at least one warship to Hawaiian waters. It also praised Midway Island as possessing a harbor surpassing Honolulu's. In the following year, Congress approved an appropriation of $50,000 on March 1, 1869, to deepen the approaches to this harbor.