1. Maryland ratifies the U.S. Constitution - On June 22, 1788, Maryland became the seventh state to ratify the U.S. Constitution, which established the federal government and its framework for laws and rights.

2. Maryland's first steamship arrives - On June 22, 1831, the steamboat "Chesapeake" arrived in Baltimore, marking the first time such a vessel had made the journey from Norfolk, Virginia to Baltimore.

3. The Battle of Saint-Mihiel begins - On June 22, 1918, during World War I, American forces led by General John J. Pershing launched an attack against German troops in the Saint-Mihiel region of France.

4. Baltimore City College becomes a landmark - On June 22, 1975, Baltimore City College was designated as a National Historic Landmark, recognizing its status as the third oldest public high school in the United States and its historic Gothic Revival architecture.

5. The Baltimore Orioles sign a historic pitcher - On June 22, 1978, the Baltimore Orioles signed pitcher Jim Palmer to a then-record contract worth $1 million per year. Palmer went on to win three Cy Young Awards and a World Series championship during his tenure with the team.