1. On April 26, 1980, the Baltimore Orioles played their first game in their new home stadium, Oriole Park at Camden Yards. The stadium's design was revolutionary, featuring a retro look and feel that has since been copied by many other Major League Baseball stadiums.

2. On April 26, 1865, the infamous assassin of President Abraham Lincoln, John Wilkes Booth, was cornered and killed by Union soldiers on a tobacco farm in Port Royal, Virginia. Booth had fled to Maryland after shooting Lincoln at Ford's Theatre in Washington, D.C.

3. On April 26, 1937, mathematician and computer pioneer Grace Hopper was promoted to the rank of lieutenant in the United States Navy Reserve. Hopper, who was born and raised in New York, spent much of her later career in Maryland, working for various government agencies and developing the first compiler for a computer programming language.

4. On April 26, 1783, a group of Maryland patriots led by Thomas Johnson and Samuel Chase met at the Maryland State House in Annapolis to officially ratify the Treaty of Paris, which ended the American Revolution and recognized the United States as an independent nation. Maryland was the last state to ratify the treaty.

5. On April 26, 1913, the Maryland General Assembly passed a law requiring all counties to establish a board of education to oversee the management of public schools. The law was part of a larger wave of education reform in the early 20th century that sought to increase access to education and improve the quality of public schools throughout the country.