Menwith Hill is a Royal Air Force station near Harrogate, North Yorkshire. On the site of the 421st Air Base Squadron is stationed, which is supported by the 501st Combat Support Wing of the United States Air Forces in Europe.
It is important for the US secret services.
According to British investigative journalist Duncan Campbell and surveillance expert, this site is part of the ECHELON network.
The 709th Military Intelligence Battalion as part of the 66th Military Intelligence Brigade of the United States Army Intelligence and Security Command is stationed here. Before 16 October 2009 was the name of the unit 109th Military Intelligence Group.
Since 1966, the National Security Agency responsible for the operation of the US portion of the plant. Some of the staff of the now-closed Bad Aibling Station was moved here.
Comparable facilities are located in Bude (UK) Sugar Grove (West Virginia, US), Yakima (Washington, US), Sabana Seca (Puerto Rico), Misawa (Japan), Pine Gap (Australia), Geraldton (Australia), Waihopai (New Zealand) and Tangimoana (New Zealand)