1. In 1861, Ohio Governor William Dennison announced that the state would provide 20,000 troops to fight in the Civil War. This was the largest contribution made by any state at the time.

2. On June 3, 1900, inventor and entrepreneur Charles F. Kettering began working at the National Cash Register (NCR) Company in Dayton, Ohio. Kettering went on to develop numerous inventions, including the first electric cash register and the first practical electric starter for automobiles.

3. The 1979 Ohio Penitentiary riot began on June 3, when prisoners in the maximum-security prison in Columbus, Ohio took control of the facility. The riot lasted for 11 days and resulted in the deaths of 10 inmates and one corrections officer.

4. On June 3, 1949, the Cleveland Indians set a Major League Baseball record by scoring 14 runs in the first inning of a game against the St. Louis Browns. The Indians went on to win the game 23-3.

5. In 1989, Ohio became the first state in the United States to celebrate Juneteenth, a holiday commemorating the end of slavery in the United States. The holiday is celebrated on June 19th in most states, but Ohio chose to celebrate it on June 3rd to coincide with the anniversary of the emancipation of Ohio's slaves in 1865.