Madison Avenue is a north-south street in the borough of Manhattan in New York City (U.S.) which carries northbound one-way traffic. It runs from Madison Square (at 23rd Street) to the Madison Avenue Bridge across the Harlem River (at 138th Street). In doing so, it passes through Midtown Manhattan, the Upper East Side (including Carnegie Hill), Spanish Harlem, and Harlem. It is named after Madison Square, which is itself named after James Madison, the fourth President of the United States. Since the 1920s, the street's name has been synonymous with the American advertising industry.