1. Battle of Monocacy: On June 24, 1864, the Battle of Monocacy took place in Frederick County, Maryland during the American Civil War. The Union forces, led by General Lewis Wallace, fought against Confederate forces led by General Jubal Early. Although the Union forces lost the battle, their efforts delayed the Confederate advance towards Washington D.C. and allowed Union forces to regroup.

2. Maryland's Flag: On June 24, 1904, Maryland's state flag was adopted. The flag features the colors and symbols of Maryland's founding families: the black and gold of the Calvert family, and the red and white of the Crossland family. The flag's design is unique among state flags, and it has become a symbol of Maryland pride.

3. Thurgood Marshall's Birthday: On June 24, 1908, future Supreme Court Justice Thurgood Marshall was born in Baltimore, Maryland. Marshall was the first African American to serve on the Supreme Court, and he was a leading advocate for civil rights during his career as a lawyer.

4. Maryland Death Penalty Repealed: On June 24, 2013, Maryland became the sixth state in the United States to repeal the death penalty. The repeal was signed into law by Governor Martin O'Malley, and it followed a long-standing debate over the morality and efficacy of capital punishment.

5. Chesapeake Bay Critical Area Act: On June 24, 1984, the Chesapeake Bay Critical Area Act was signed into law. The law established regulations for development and land use within 1,000 feet of the Chesapeake Bay shoreline, in order to protect the Bay's fragile ecosystem. The law has been credited with reducing pollution and preserving Maryland's coastal environment.