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. Opened in 1874, 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.
At 520 feet between the piers, the center arch of Eads Bridge was the longest rigid span ever built at the time of its construction (only a few suspension bridges had longer spans). It remained the longest rigid span until the completion of the 525 foot (160 meter) arch of Gustave Eiffel's Maria Pia Bridge, in Porto, Portugal, in 1877.
In addition to its age and size, Eads Bridge is noted for the material used in its construction. Much of the metal in the bridge is wrought iron but the primary load-carrying components of the arches were made from steel. This was the first large-scale application of steel as a structural material and initiated the shift from wrought-iron to steel as the default material for large structures.
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 new Stan Musial Veterans Memorial Bridge opened in February 2014.
According to en.wikipedia