The United Nations is headquartered in New York City in a complex designed by a board of architects led by Wallace Harrison and built by the architectural firm Harrison & Abramovitz. The complex has served as the official headquarters of the United Nations since its completion in 1951. It is in the Turtle Bay neighborhood of Manhattan, on 17 to 18 acres of grounds overlooking the East River. Its borders are First Avenue on the west, East 42nd Street to the south, East 48th Street on the north, and the East River to the east. The term Turtle Bay is occasionally used as a metonym for the UN headquarters or for the United Nations as a whole.
The headquarters holds the seats of the principal organs of the UN, including the General Assembly and the Security Council, but excluding the International Court of Justice, which is seated in the Hague. The United Nations has three additional subsidiary regional headquarters, or headquarters districts. These were opened in Geneva in 1946, Vienna in 1980, and Nairobi in 1996.