1. On March 21, 1872, the Idaho territorial governor, Caleb Lyon, was removed from office due to corruption charges. He was the first and only territorial governor to be impeached in Idaho's history.

2. March 21, 1961, marked the opening of the Idaho National Laboratory, a research facility that focuses on nuclear energy and national security. It is the nation's leading center for nuclear research and development.

3. In 1969, on March 21, the first major earthquake in the Boise area since 1904 occurred. It measured 6.5 on the Richter scale and caused widespread damage in the city.

4. On March 21, 1989, Idaho became the 26th state to observe Martin Luther King Jr. Day as a state holiday. The holiday honors the legacy and achievements of the civil rights leader.

5. March 21, 2001, marked the opening of the Boise State University Student Union building. It is a central gathering place for students and has since become a hub for student activities and events.