1. Maryland was the 7th state to ratify the United States Constitution on June 5, 1788. This made Maryland the first state to approve the document after Delaware and Pennsylvania ratified it five months earlier.

2. On June 5, 1837, the Baltimore and Ohio Railroad completed its line from Baltimore to Wheeling, West Virginia, becoming the first railroad to connect the eastern and western regions of the United States.

3. The first public museum in the United States, the Peale Museum, opened in Baltimore on June 5, 1814. The museum was founded by Charles Willson Peale, an American painter, soldier, and naturalist, and is notable for its collection of portraits of American Revolutionary War figures.

4. On June 5, 1968, Senator Robert F. Kennedy was assassinated at the Ambassador Hotel in Los Angeles, California, while campaigning for the Democratic presidential nomination. Kennedy had won the Maryland primary two months earlier, and his assassination deeply affected the state and the nation.

5. In June 2003, the United States Supreme Court upheld the University of Michigan's affirmative action policy, which awards extra points to minority applicants. The ruling was announced on June 5, and was seen as a major win for supporters of affirmative action in Maryland and across the country.