The Francis Scott Key Bridge, also known originally as the Outer Harbor Crossing (until renamed for FSK in 1977) or simply as the Key Bridge or Beltway Bridge, is a steel arch-shaped continuous through truss bridge spanning the lower Patapsco River and outer Baltimore Harbor / Port in Baltimore, Maryland, U.S.A.. The main span of 1200 feet is the third longest span of any continuous truss in the world.