1. Kent State Shootings - On May 4, 1970, four unarmed students were killed and nine others were wounded when members of the Ohio National Guard opened fire on a crowd of demonstrators protesting against the Vietnam War on the campus of Kent State University.

2. Great Dayton Flood - On May 4, 1913, a massive flood swept through the city of Dayton, Ohio and its surrounding areas, killing over 360 people and causing millions of dollars in damages.

3. Ohio Statehood - May 4, 1803 marks the day when Ohio officially became the 17th state of the United States.

4. First Professional Baseball Game - On May 4, 1871, the first official professional baseball game was played between the Fort Wayne Kekiongas and the Cleveland Forest Citys. The game ended in a 2-0 victory for Fort Wayne.

5. Ohio Supreme Court landmark decision - On May 4, 1954, the Ohio Supreme Court made a landmark decision when it ruled that segregation in public schools was unconstitutional, well before the famous Brown v. Board of Education Supreme Court decision in 1954 that ended legal segregation across the United States.