1. Pennsylvania's first state-owned and operated liquor store opened on March 15, 1934. The store, located in Harrisburg, was a product of the state's Liquor Control Board, which was formed in response to the repeal of Prohibition.

2. The Battle of Guilford Courthouse, a major Revolutionary War engagement between British forces and the Continental Army, took place on March 15, 1781. Despite suffering heavy casualties, the Continental Army inflicted enough damage on the British to force their retreat.

3. On March 15, 1792, the Pennsylvania General Assembly passed an act that enabled the establishment of the first free public school system in the United States. The law required each township in the state to establish a school, with funding provided by the state.

4. In 1965, singer and civil rights activist Marian Anderson became the first Black person to perform at the Metropolitan Opera House in New York City. Anderson, who had been denied the opportunity to perform at Philadelphia's Constitution Hall because of her race, was celebrated in her hometown of Philadelphia on March 15 with a parade and other events.

5. On March 15, 1972, a massive flood caused by heavy rain and melting snow devastated communities throughout the state, particularly in the Susquehanna River Valley. The flood resulted in the deaths of dozens of people, destroyed thousands of homes, and caused billions of dollars in damage. The disaster led to the creation of the Pennsylvania Emergency Management Agency, which continues to provide disaster relief services in the state today.