Kenneth Arnold UFO Sighting, Boise, Idaho (June 1947)
A June 1947 government report details an unidentified object sighting in Boise, Idaho, involving nine saucer-like objects moving in a chain-like formation.
Background
In June 1947, in Boise, Idaho, U.S. government investigators recorded an unidentified-object incident later released to the
public on May 8, 2026, as part of the Presidential Unsealing and Reporting System for UAP Encounters (PURSUE). This specific report emerged during a period of heightened atmospheric anxiety in the United States, occurring within the first wave of “flying saucer” reports that swept the nation following the Kenneth Arnold sighting in June 1947 and the Roswell incident of July 1947. During this post-war era, the sudden appearance of unidentified aerial phenomena prompted significant concern regarding national security and the integrity of airspace.
The documentation of this Boise incident was processed through established bureaucratic channels. The case was filed with the Federal Bureau of Investigation, whose Knoxville, Albuquerque, Los Angeles, and other field offices routed UFO reports to headquarters under the Bureau’s standing protocols for the protection of vital installations. This systematic routing suggests that, at the time, the federal government viewed these sightings through the lens of potential threats to sensitive military and industrial infrastructure, treating unidentified objects as matters of domestic intelligence and surveillance.
What the document records
The released file contains observations of unidentified objects characterized by their distinct movement and appearance. Kenneth Arnold, while flying his private plane, observed nine distant, saucer-like objects moving at high speeds near Mount Rainier. He described them as flat, shiny, and reflecting sunlight, moving in a chain-like formation. The objects appeared to be swerving in and out of the mountain peaks. While the visual characteristics of the objects were detailed, the number of witnesses is not specified in the released document.
The physical description provided in the report emphasizes the reflective nature of the objects and their unusual flight patterns. The objects were described as being disc- or saucer-shaped, a descriptor that became a hallmark of the era’s aerial phenomenon reports.
Verbatim from the file
The primary evidence within the investigative file consists of direct observations recorded by the witness. The report includes the following statements: “I could see their outline quite plainly against the snow as they Approached the mountain.” The movement of the objects was noted as being highly erratic yet organized, with the witness stating, “They flew very close to the mountain tops, directly south to south-east down the hog’s back of the range, flying like geese.” The visual appearance of the objects was further clarified by the description, “They were flat like a pie pan and so shiny they reflected the sun like a mirror.”
Type of case
The witnesses described the object as disc- or saucer-shaped. This shape became the standard nomenclature for many reports during the late 1940s, influencing both public perception and the subsequent classification of unidentified aerial phenomena.
Status
All records released under the PURster program are designated unresolved by the All-domain Anomaly Resolution Office (AARO) by default. The federal government has not concluded that the events were anomalous, has not concluded that they were conventional, and has not ruled out either possibility.
The investigation of such sightings in the mid-twentieth century often grappled with a lack of advanced radar technology and the emergence of new aeronautical developments. Conventional candidates for sightings of this period include experimental aircraft, weather balloons, especially the Project Mogul series in the late 1940s, and atmospheric optical phenomena such as sundogs and lenticular clouds. Additionally, astronomical objects including Venus, the Moon, and meteors near the horizon were frequently considered as potential explanations for reported unidentified objects.