The Third Avenue Bridge carries southbound road traffic on Third Avenue over the Harlem River, connecting the boroughs of Manhattan and the Bronx in New York City. It once carried southbound New York State Route 1A. The Third Avenue Bridge carries traffic south from the intersections of either Third Avenue and East 135th Street, or Bruckner Boulevard and Lincoln Avenue, in the Bronx.

On the Manhattan side, the bridge funnels traffic into three locations: East 128th Street; the intersection of East 129th Street and Lexington Avenue; or the southbound Harlem River Drive in Manhattan. The bridge was formerly bidirectional, but converted to one-way operation southbound on August 5, 1941 on the same day the Willis Avenue Bridge was similarly converted to one-way northbound.

In 1955, the original multi-truss bridge constructed in 1898 was removed and sold.[4] A rebuilt bridge reopened in December 1956. The initial deck carried two trolley tracks, which were eliminated in 1928 during a reconstruction effort to accommodate automobiles. In the early 1900's, electric operating equipment replaced the original steam equipment.