June 24, 1947, was the first Official UFO reported. Kenneth Arnold filed a report on an unidentified flying object he sighted while flying near Mt. Rainier, in Washington state.
The report was the first to have nationwide news coverage and is credited with being the first of the modern era of UFO sightings, including numerous reported sightings over the next two to three weeks. Arnold's description of the objects also led to the press quickly coining the terms flying saucer and flying disc as popular descriptive terms for UFOs.