Pearl Harbor

Naval base and headquarters of the U.S. Pacific Fleet, Honolulu county, southern Oahu Island, Hawaii, U.S. In U.S. history the name recalls the Japanese surprise air attack on Dec. 7, 1941, that temporarily crippled the U.S. Fleet and resulted in the United States' entry into World War 2. Pearl Harbor centres on a cloverleaf-shaped, artificially improved harbour on the southern coast of Oahu, 6 miles (10 km) west of Honolulu. The harbour is virtually surrounded (west to east) by the cities of Ewa, Waipahu, Pearl City, Aiea, and Honolulu.

It has 10 square miles (26 square km) of navigable water and hundreds of anchorages and covers a land area of more than 10,000 acres (4,000 hectares). Its four lochs are formed by the Waipio and Pearl City peninsulas and Ford Island. Pearl Harbor Entrance (channel) connects its virtually landlocked bay with the Pacific Ocean.

Pearl Harbor was called Wai Momi ("pearl waters") by the Hawaiians because of the pearl oysters that once grew there. In 1840 Lieutenant Charles Wilkes of the U.S. Navy made the first geodetic survey and urged the dredging of the coral-bar entrance to the harbour. About 30 years later, Colonel John McAllister Schofield further recommended that the United States secure harbour rights.

A subsequent treaty (1887) granted the United States the