1. The first ever statewide primary election in Idaho was held on May 27, 1930, allowing voters to directly choose their candidates for the general election.
2. On May 27, 1942, a Japanese submarine fired shells at Fort Stevens on the Oregon coast, making it the only time during World War II that the continental United States was attacked by enemy forces.
3. In 1965, on May 27, a tumultuous civil rights protest occurred in Lewiston, Idaho, where African American demonstrators were met with fierce resistance and violence by white residents and police.
4. Boise State University, one of the largest universities in Idaho, received its charter on May 27, 1974, officially establishing its existence.
5. The Idaho Vandals, the collegiate athletics team of the University of Idaho, won the NCAA men's Division I national outdoor track and field championship on May 27, 1982, marking the school's first and only national championship in any sport.