1. On February 21, 1828, the Maryland State Colonization Society was formed in Baltimore. Its mission was to encourage free African Americans in Maryland to emigrate to Liberia, a country in Africa. The Society believed that this would help to solve the problem of slavery in the United States, by removing free African Americans from the country.

2. In 1848, the Maryland State Senate rejected a bill that would have abolished slavery in the state. The bill was proposed by a group of abolitionists, but it failed to pass by a vote of 6-16. Maryland would not abolish slavery until the adoption of the 13th Amendment to the U.S. Constitution in 1865.

3. On February 21, 1861, the secession convention in Baltimore voted unanimously to secede from the United States and join the Confederate States of America. However, the move was never recognized by the federal government and Maryland remained in the Union during the Civil War.

4. In 1918, the first African American to earn a Ph.D. from Johns Hopkins University in Baltimore was awarded his degree. Dr. Elmer Samuel Imes went on to become a renowned physicist and was recognized for his work in spectroscopy and molecular physics.

5. The Maryland House of Delegates declared February 21, 1976, to be Barbara Mikulski Day in honor of the Baltimore-born politician who had been elected to the U.S. House of Representatives the previous year. Mikulski went on to serve in the U.S. Senate, becoming the longest-serving woman in the history of Congress at the time of her retirement in 2017.