[Army Times] Nestled in a quiet Virginia county called Fauquier is an isolated farmhouse that’s been in use since 1803, including as a dairy. Originally referred to as "Vint Hill," FOIA records from NSA show that it had several owners before it was purchased by the Army in 1942.Situated in convenient proximity to the Signal Intelligence Service headquarters in Arlington, but still located far enough from the city to remain secretive, Vint Hill proved the perfect place for the Army to house a spy base: Monitoring Station No. 1.
The geography was the key. Evidently, its "location and quiet electromagnetic geology" made it a prime spot for intercepting radio signals abroad, reported Smithsonian Magazine. And during World War II, soldiers stationed there did just that.
"Private Leonard A. Mudloff intercepted a message from the Japanese ambassador to Germany in 1943 that described German fortifications, troop strength and contingency plans in western France," the Fauquier Times wrote. "Once decoded, that information aided the Allies in planning the successful D-Day invasion of June 6, 1944."
According to the documents released by the NSA, the station was a crucial intelligence-gathering mechanism throughout World War II and beyond. Additional Army resources classified Vint Hill Farms Station at one point as one of the largest intercept facilities in the world.