1. In 1778, the Continental Congress voted to appoint Major General Baron von Steuben as Inspector General of the Continental Army. Although the Prussian military officer would train soldiers throughout the colonies, he would eventually settle in Maryland, where he would live until his death in 1794.

2. The Chesapeake and Ohio Canal, a 184.5 mile-long canal that connected Washington, D.C. to Cumberland, Maryland, was completed on May 15, 1850. The canal helped to transport coal, grain, and other goods from western Maryland to the East Coast.

3. On May 15, 1862, President Abraham Lincoln signed into law the Homestead Act, which gave settlers the opportunity to claim up to 160 acres of public land if they agreed to live on the land for at least five years and cultivate it.

4. The Supreme Court of the United States issued a ruling on May 15, 1961 in the landmark case Edwards v. South Carolina. The court ruled that peaceful demonstrations are protected by the First Amendment and that states cannot use their police power to suppress these demonstrations.

5. In 1970, Governor Marvin Mandel signed a bill into law that reinstated the death penalty in Maryland. The state had not executed a prisoner since 1961, but the law allowed for the death penalty to be used in cases of first degree murder. The death penalty would be abolished in Maryland in 2013.