UFO Sighting Report — Longmont, Colorado, July 1957

This document contains a U.S. Air Force Technical Information Sheet and accompanying correspondence regarding a UFO sighting that occurred in July 1957 near Longmont, Colorado. The witness, a civilian rancher, reported observing a craft while raking hay on his property during the early morning. He described the object as a large, metallic, disk-shaped craft, approximately 150 to 200 feet in diameter, with a honeycomb-patterned top that resembled blue glacier ice and a smooth, silver-colored bottom featuring kidney-shaped designs. The witness noted that the object hovered at an altitude of roughly 400 feet, maintaining a rocking motion similar to a falling maple leaf. The craft made no sound and produced no visible air disturbance, such as smoke or vapor trails. After hovering for approximately ten minutes, the object rose vertically, tilted, and accelerated at a tremendous rate in an arc toward the south-southwest. The witness initially mistook the object for a falling meteor but quickly realized it was a manufactured craft. He provided detailed sketches of the object's top and bottom surfaces to Dr. J. Allen Hynek of Northwestern University in a letter dated October 14, 1964. The witness explicitly stated that he had not seen any living creatures and assumed the craft might be piloted by the Air Force. The official Air Force conclusion for the incident was 'UNIDENTIFIED.' The investigating officer, Dr. Hynek, noted that the eight-year delay in reporting the incident made a thorough investigation difficult, as the sighting was no longer fresh in the witness's mind, though no plausible explanation for the event was found.