free port, port, or section of a port, exempt from customs regulations (see tariff). Goods may be landed at a free port for storage and handling, and they may even be processed into manufactured goods. Duty is charged only if the goods are moved from the free port into the adjacent territory. Free ports originated in the late Middle Ages, when the burdensome tariffs charged by many petty states threatened the reemerging maritime commerce. The high tariffs later levied in the period of mercantilism necessitated additional free ports. In the 19th cent. the danger of smuggling caused the closing of many free ports. In Europe, Copenhagen, Danzig, and Hamburg were free ports until 1939; in East Asia, Hong Kong and Singapore still are. In the United States, bonded warehouses serve some of the functions of the free port, permitting goods to be stored and processed in specially licensed warehouses if a bond exceeding the amount of the customs duties is first posted. In 1934 the Foreign Trade Zones Act authorized the establishment of free ports in the United States, but with a prohibition on manufacturing. The first American free port was opened in New York City in 1937, and others have since been added. Many international airports have free ports.