The following events happened in the year 1947:
- June 21 - UFO wave of 1947
- June 24 - Kenneth Arnold witnesses the first recorded sighting of a “flying saucer” near Mount Rainier, Washington.
- June 27 - Harold Dahl sighting, in Pudget Sound, involved in first reported encounter with Men in Black.
- July 2 - after 9:50 p.m. Socorro Incident of a UFO crash at Plains of San Agustin near Socorro, New Mexico.
- July 2 - after 9:50 p.m. Roswell Incident of a UFO crash at Foster Ranch near Roswell, New Mexico.
- July 9 -Alien interview #1
- July 10 - Alien interview #2
- August 1 - interrogation of MSgt. Matilda O'Donnell, Roswell Airfield US
- July 23 - The Bauru incident in Bauru, São Paulo, involving the abduction of topographer José Higgins in a Close Encounter of the fifth kind.
- September 17 - James Forrestal is made the first US Secretary of Defense.
- September 18 - United States Department of Defense (DoD) is established.
- September 18 - Central Intelligence Agency (CIA) is established.
- September 18 - United States Air Force (USAF) is re-outfitted as an independant arm of the United States.
- September 24 - Harry Truman begins Operation Majority Twelve (See Majority 12).
- December -Project Sign begins, conducted by the USAF.
- Picknett, Lynn. The Mammoth Book of UFOs, p. 137—location of Socorro crash-site per Vernon Malthais, October 1978
- The Vault, https://vault.fbi.gov/Majestic%2012/Majestic%2012%20Part%201%20of%201/view
- Telegraph, Aliens have deactivated British and US nuclear missiles, say US military pilots, by Andy Bloxham, 27 Sep 2010