The Old Chain of Rocks Bridge crosses the Mississippi River on old US 66. It is south of the I 270 Bridge.
The bridge was built as a private venture toll bridge. The projected cost was 1.2 million. The builders were: the American Bridge Company of New York, Barter Brown, and the Union Bridge and Construction Company of Kansas City.
It was originally projected to be a straight bridge over the Mississippi. However, due to a few circumstances, it has a 24 degree bend.
Work commenced at both ends of the bridge in 1927. It concluded in 1929. It officially opened on July 5, 1929.
The bridge is made of 11 Warren truss sections. The 3 longer sections span the river. There are 3 shorter sections on the Missouri side. There are 5 shorter sections on the Illinois side. The bridge supports are massive concrete piers the tops of which are 55 feet above the water. Total construction costs were $ 2.5 million
The private venture that built the bridge went bankrupt in 1931. Bridge ownership reverted to the city of Madison in 1939. The bridge became US 66 in 1936. In 1955, US 66 was transferred to I 270. The Chain of Rock Bridge became US 66 Bypass. The bridge closed to traffic in 1968. It reopened as a pedestrian bridge on June 5,1999.
The bridge total length is 5,353 feet. Width is 24 feet.
. It was listed on the National Register of Historic Places in 12/1/2016.