Mary Pickersgill was the maker of the Star-Spangled Banner hoisted over Fort McHenry during the Battle of Baltimore in the War of 1812. The daughter of another noted flag maker, Rebecca Young, Pickersgill learned her craft from her mother, and in 1813 she was commissioned by Major George Armistead to make a flag for Baltimore's Fort McHenry that was so large that the British would have no difficulty seeing it from a great distance. The flag was installed in August 1813 and, during the Battle of Baltimore a year later, Francis Scott Key could see the flag while negotiating a prisoner exchange aboard a British vessel and was inspired to pen the words that became the United States National Anthem in 1931.

The Star-Spangled Banner, or the Great Garrison Flag, was the garrison flag that flew over Fort McHenry in Baltimore Harbor during the naval portion of the Battle of Baltimore during the War of 1812. It is on exhibit at the National Museum of American History, Smithsonian Institution. Seeing the flag flying over Fort McHenry on the morning of September 14, 1814, after the battle ended, Francis Scott Key was inspired to write the poem "Defence of Fort M'Henry". These words were written by Key and set to the tune of "To Anacreon in Heaven", a popular song at the time, by John Stafford Smith. In 1931 the song became the national anthem of the United States.