Peoria, IllinoisAugust 1953

On August 17, 1953, two separate incidents occurred in the Peoria, Illinois area involving unidentified flying objects observed by multiple civilians, along with radar operators at a nearby military facility.

In Peoria, two civilian observers reported seeing a single bright white object about the size of a baseball at 1445 (2:45 p.m.) CST. The object appeared to be suspended in the air, then moved slowly away toward the south-southeast. At roughly the same time, personnel at the 791st Air Control and Warning Squadron station in Hanna City, Illinois, located about thirty miles away, observed a different object that was half-moon shaped in the same general area. The total observation time across both sightings was about 30 minutes.

The Air Force investigation that followed was thorough but inconclusive. The Hanna City radar unit detected no unusual tracks on radar during the sighting. Investigators checked with the local weather station and confirmed that no weather balloons had been released in the area at that time. They also checked with nearby airfields and found no aircraft in the vicinity. However, they did discover that an upper air research balloon was in the area over Peoria at the time of the sighting.

Based on these findings, the Air Force concluded that the object was likely a balloon (the case file states "Was balloon"). However, the evidence remains somewhat ambiguous. While a balloon would account for the sighting, the shape discrepancies between observer reports and the lack of definitive correlation make this conclusion less than absolute.

The full 37-page case file is reproduced below as held by the National Archives.