Project Blue Book Case #483. On July 24, 1949, an unidentified object was observed near Mountain Home, Idaho — home to Mountain Home Air Force Base, a SAC installation in the high desert of the Snake River Plain. Mountain Home AFB hosted bomber and fighter units tasked with the nuclear deterrent mission.
The Snake River Plain's vast, flat expanse of sagebrush and lava rock provided unlimited visibility and some of the darkest skies in the western states. Mountain Home sits at approximately 3,000 feet elevation, surrounded by terrain so empty that the nearest significant town is Boise, 50 miles to the northwest.
July 1949 was during the Project Grudge era. The case was classified "Unknown" — a notable designation from one of SAC's more remote bomber bases in the Pacific Northwest.