What was the name of the 15-star, 15-stripe flag that inspired the U.S. national anthem?

The 15-star, 15-stripe flag that inspired the U.S. national anthem was the Star-Spangled Banner.

The huge garrison flag flew over Fort McHenry in Baltimore Harbor during the Battle of Baltimore in the War of 1812. Francis Scott Key saw it still flying on the morning of September 14, 1814, after the British bombardment, and wrote the poem “Defence of Fort M’Henry.”

The flag had 15 stars and 15 stripes, representing the United States after Vermont and Kentucky joined the Union. It is the only official U.S. flag to have had more than 13 stripes; Congress later returned the stripe count to 13 while continuing to add stars for new states.

The poem was set to the melody “To Anacreon in Heaven.” In 1931, the song officially became the national anthem. The original flag is preserved at the Smithsonian’s National Museum of American History.