1. In 1816, Thomas Jefferson wrote a letter to Virginia politician Spencer Roane, expressing his thoughts on the separation of powers and the limits of federal authority in the United States. This letter is now known as the "Kentucky Resolutions," and is considered a key document in the history of American constitutional law.

2. In 1860, Virginia held a statewide referendum on the question of secession from the Union. The majority of voters supported secession, and the state formally withdrew from the United States several months later, becoming part of the Confederacy.

3. In 1928, Virginia Governor John Garland Pollard signed into law a bill that established the Virginia State Police, replacing the patchwork of local and county law enforcement agencies that had existed previously. The State Police continue to play a vital role in maintaining public safety in Virginia today.

4. In 1947, a massive explosion occurred at the Olean Oil Refinery in Accomack County, killing three workers and causing extensive damage to the facility. The cause of the explosion was never determined, but it was one of the worst industrial accidents in Virginia's history.

5. In 2012, Virginia became a key battleground state in the 2012 presidential election, as President Barack Obama and Republican challenger Mitt Romney each campaigned heavily in the state. Obama ultimately won Virginia by a narrow margin, contributing to his re-election victory.