The star spangled banner is the national anthem of which country?

“The Star-Spangled Banner” is the national anthem of the United States. By the time the song officially became the country's anthem in 1931, it had been one of America's most popular patriotic tunes for more than a century. Key was inspired by the large U.S. flag, with 15 stars and 15 stripes, known as the Star-Spangled Banner, flying triumphantly above the fort during the U.S. victory.