1. On June 15, 1836, the Baltimore and Ohio Railroad completed its first commercial train journey from Baltimore to Ellicott's Mills, which is now known as Ellicott City. This marked a major milestone in the transportation industry and contributed greatly to the growth of Baltimore as a major port city.

2. In 1863, the Battle of Second Winchester took place in Virginia, just south of the Maryland state line. The battle was part of the Gettysburg Campaign during the Civil War and resulted in a Confederate victory.

3. The United States Naval Academy was established on June 15, 1845, in Annapolis, Maryland. The Academy is one of the most prestigious military institutions in the world and has produced many notable alumni, including Presidents Jimmy Carter and George H.W. Bush.

4. On June 15, 1939, the first Navy recruits arrived at the newly-constructed Naval Training Center at Bainbridge, Maryland. The facility was used to train Navy personnel throughout World War II and was eventually decommissioned in 1976.

5. In 1991, the Maryland National Guard was mobilized to respond to the eruption of Mount Pinatubo in the Philippines. The Maryland Guard provided logistical and transportation support to U.S. military personnel and civilians affected by the disaster.