1. On April 3, 1974, the Kentucky Derby Museum officially opened to the public. The museum is located at Churchill Downs, the historic racetrack that hosts the annual Kentucky Derby.

2. On April 3, 1792, Kentucky became the 15th state to join the United States. The state was initially a part of Virginia before gaining statehood.

3. On April 3, 1860, the first regularly scheduled passenger train crossed the Ohio River from Cincinnati, Ohio to Covington, Kentucky. This marked a significant transportation milestone for the state and opened up many new economic opportunities.

4. On April 3, 1963, civil rights leader Dr. Martin Luther King Jr. visited Louisville, Kentucky and gave a speech at the Memorial Auditorium. In his speech, he called for an end to segregation and discrimination in the United States.

5. On April 3, 2017, a Special Election was held in Kentucky's 4th congressional district to fill the seat left vacant by Rep. Thomas Massie's resignation. Republican candidate Vacant won the election, securing the seat for the party.