Congress adopted “The Star-Spangled Banner” as the U.S. national anthem in 1931.
President Herbert Hoover signed the law on March 3, 1931, giving the song official national-anthem status. Before that date, the United States had used several patriotic songs at public events, including “Hail, Columbia” and “My Country, ’Tis of Thee.”
The lyrics originated in a poem written by Francis Scott Key in 1814 after he saw the American flag flying over Fort McHenry during the Battle of Baltimore. The poem was titled “Defence of Fort M’Henry” and was later set to the tune of a British song.
The song’s wartime origin is often confused with its later legal adoption. It became culturally prominent during the 19th century, but it was not officially designated the national anthem until more than a century after Key wrote the poem.