1. Ohio Became a State: On March 4, 1803, Ohio officially became a state in the United States of America. It was the first state to join the Union that was located west of the Appalachian Mountains.

2. Prohibition Ended: March 4, 1933, marked the end of Prohibition in Ohio. This was a significant legislative change that allowed residents of Ohio to consume alcohol for the first time in over a decade.

3. William Henry Harrison Inaugurated: William Henry Harrison, who would later become the 9th President of the United States, was inaugurated as governor of the Indiana Territory on March 4, 1801. The Indiana Territory included what is now the state of Ohio.

4. First Black Ohio State Senator: On March 4, 1963, Robert A. Grier became the first African American to serve in the Ohio Senate. He represented the 25th Senate District and served for two terms.

5. Ohio State University Founded: On March 4, 1870, Ohio Governor Rutherford B. Hayes signed a bill to establish Ohio Agricultural and Mechanical College. This later became Ohio State University, one of the largest universities in the United States.