Chicago Area Mass Sighting 1966

On April 5, 1966 — one day before the famous Ann Arbor–Dexter Michigan and Portage County Ohio events — Chicago experienced a major mass sighting lasting 45 minutes. Over 500 civilian calls flooded Chicago Police Department. O'Hare Airport tower controllers confirmed multiple disc-shaped radar contacts at 1,000 to 5,000 feet altitude in controlled airspace. Multiple CPD units observed the objects visually. The discs were described as approximately 60–100 feet in diameter, metallic, and moving in loose formation before executing coordinated maneuvers. O'Hare ATC filed a NOTAM and contacted Air Defense Command. The FBI's Chicago field office, operating under the Bureau's standing reporting protocol for disc sightings near major population centers, conducted a parallel investigation to the USAF Blue Book inquiry. The cross-referencing of the Chicago case with the Ann Arbor events the following day suggested to investigators that the wave was moving eastward across the Great Lakes region.