The Eads Bridge is a combined road and railway bridge over the Mississippi River connecting the cities of St. Louis, Missouri and East St. Louis, Illinois. It is located on the St. Louis riverfront between Laclede's Landing, to the north, and the grounds of the Gateway Arch, to the south. The bridge is named for its designer and builder, James Buchanan Eads. Work on the bridge began in 1867, and it was completed in 1874. The Eads Bridge was the first bridge across the Mississippi south of the Missouri River. Earlier bridges were located north of the Missouri, where the Mississippi is smaller. None of the earlier bridges survive, which means that the Eads Bridge is also the oldest bridge on the river.
In order to accommodate the massive size and strength of the Mississippi River, the Eads Bridge required a number of engineering feats. Perhaps most importantly, due to the use of steel by Andrew Carnegie’s Keystone Bridge Company, it was the first large-scale use of steel as a structural material and initiated the shift from wrought-iron to steel as the default material for large structures. Its foundations were the deepest underwater constructions at the time, at more than 100 feet below water level. They were installed using pneumatic caissons, a pioneering application of caisson technology in the United States and, at the time, by far the largest caissons ever built. Its center arch was the longest rigid span ever built at the time, at 520 feet. The method of constructing the arches, in which they were suspended from temporary wooden towers, is sometimes cited as the first use of the "cantilever principle" for a large bridge. These engineering principles were used for later bridges, including the Brooklyn Bridge, which began construction in 1870.
The Eads Bridge became a famous image of the city of St. Louis, from the time of its erection until 1965 when the Gateway Arch was completed. The highway deck was closed to automobiles from 1991 to 2003, but has been restored and now carries both vehicular and pedestrian traffic. It connects Washington Avenue in St. Louis, Missouri with Riverpark Drive and, eventually, East Broadway, both in East St. Louis, Illinois. The former railroad deck now carries the St. Louis MetroLink light rail system, providing service between St Louis and communities on the Illinois side of the river.
The bridge is listed on the National Register of Historic Places as a National Historic Landmark. As of April 2014, it carries about 8,100 vehicles daily, down 3,000 since the Stan Musial Veterans Memorial Bridge opened in February 2014.