1. On September 27, 1908, Idaho became the first state in the United States to adopt a statewide initiative and referendum process, which allows citizens to propose and vote on laws and constitutional amendments, bypassing the state legislature.

2. The first football game between two Idaho colleges was played on September 27, 1915, when Idaho State University defeated the College of Idaho 20-7. The rivalry between the two schools, known as the "Battle of the Domes," continues to this day.

3. On September 27, 1933, the Air Mail Act was signed into law, which allowed private airlines to operate airmail routes and led to the expansion of commercial aviation in the United States. Several airlines, including Western Air Express and United Airlines, began operating in Idaho during this time.

4. The Anderson Dam, located in southwestern Idaho, was completed on September 27, 1973, after several years of construction. The dam, which is 221 feet tall and stretches 3,000 feet across the Boise River, helps provide irrigation water for local farms and generates hydroelectric power for the surrounding area.

5. On September 27, 2017, a magnitude 5.3 earthquake struck southeastern Idaho, followed by several aftershocks. The quake was felt throughout the state and caused some minor damage, but no injuries were reported. It was the largest earthquake to hit Idaho since 1983.