Pentagon Documents Detail High-Speed ‘Black Triangle’ Sighting Over U.S. National Security Site
Newly released Pentagon files have detailed a startling encounter between federal agents and a mysterious “black triangle” craft earlier this year near a sensitive national security site in the western United States. The declassified documents describe a matte black object with an extremely low aspect ratio that exhibited flight characteristics seemingly beyond the capabilities of conventional aviation technology.
According to an FBI observation report included in the files, two federal agents were stationed at an observation post several miles west of the undisclosed national security site in June when they were alerted to the presence of an anomaly. The agents initially detected what they termed a “thermally elevated aerial object” through surveillance equipment before moving to a better vantage point for a direct visual assessment. Upon spotting the craft, they described it as a substantial, non-reflective, dark black triangular object that most closely resembled a delta-wing drone, though they noted several anomalous features.
The agents provided specific dimensions for the craft, estimating its wingspan at between 9 and 15 feet, its depth at 6 to 9 feet, and its thickness at only 1 to 2 feet. Despite being significantly “hotter than ambient temperature,” the object reportedly produced no visible exhaust gases and moved without any detectable acoustic signature, remaining silent throughout the encounter.
A separate Department of War memorandum corroborated the sighting, incorporating data from a third official at a different observation post who used long-range thermal equipment. This memorandum provided a precise timeline of the craft’s movements. The unidentified craft reportedly made a vertical ascent for approximately 10 seconds, reaching an estimated altitude of 200 to 300 feet above a local ridge line. After what was described as an “instantaneous” arrest of its vertical motion, the object entered a stable hover for about 20 seconds.
The most dramatic portion of the report details the craft’s departure. From a zero-velocity hover, it transitioned directly into high-speed horizontal flight, which observers described as being “as fast as a fighter jet.” During this phase, the object executed a fluid banking maneuver and a terrain-hugging descent into a canyon drainage, covering the distance in approximately two to three seconds before disappearing from view.
While the documents include several photographs—some of which feature representations of the object superimposed over the local landscape—many specific details remain redacted, including the exact location of the national security site. The release of these files is part of a broader effort toward public disclosure regarding unidentified aerial phenomena, a process accelerated by a previous presidential directive from the Trump administration to increase transparency surrounding mysterious objects in U.S. airspace.
