Montana is the fourth-largest U.S. state by area, a Mountain West state whose eastern 60 percent is prairie of the northern Great Plains. It borders British Columbia, Alberta and Saskatchewan, and its capital is Helena. Its UFO history centers on Great Falls and on Malmstrom Air Force Base, chosen in 1959 to host the Minuteman I intercontinental ballistic missile; the base's launch facilities later formed the largest ICBM field in the United States, about 23,500 square miles of central Montana.

On August 15, 1950, Nick Mariana, general manager of the Great Falls Electrics baseball team, used a 16 mm camera to film two bright, silvery objects over the city's Legion Stadium for about 16 seconds. Air Force analysts first attributed the Great Falls film to reflections from two F-94 jets. After a 1952 re-examination, Project Blue Book chief Edward Ruppelt wrote that "it was an unknown," while the 1953 Robertson Panel judged the objects reflections of aircraft known to be in the area. Mariana said the first 35 frames were missing when the film came back; the Air Force said it had removed one damaged frame. For the Condon Committee, William Hartmann judged airplanes unlikely but not entirely ruled out.

Montana's other major case is the 1967 Malmstrom incident. An Air Force report records that all sites in Echo Flight shut down with no-go indications on March 16, 1967, and says rumors of UFOs near the flight were disproven. Former launch officer Robert Salas has said guards reported a glowing red object hovering above the front gate of his launch control facility as missiles went offline that month. A 2025 Wall Street Journal report said the shutdowns were caused by a classified electromagnetic-pulse test, an account Salas has rejected, and in March 2026 the New York Post carried a former missile officer's renewed claim that UFOs disabled the base's missiles.

The Great Falls film returned to the federal record in August 2026, when Release 05 of the Department of War's PURSUE files included DOW-UAP-D098, a Navy photographic analysis of the Montana film and the 1952 Tremonton, Utah, film. According to LA Magazine's account of the file, the analysts said they could not identify the objects as natural phenomena or man-made objects, while cautioning that their conclusions might not reflect the Navy's official position. Montana thus holds two long-running American UFO cases: a 1950 color film whose explanation shifted between Air Force reviews, and a nuclear-missile outage whose cause is still disputed.