The old Chain of Rocks Bridge spans the Mississippi River on the north edge of St. Louis, Missouri, United States.

Its most notable feature is a 22-degree bend occurring at the middle of the crossing, which was found to be necessary during construction due to both the presence of a water intake and the inability of parts of the bedrock of the river to carry the weight of the bridge.

[3] The bridge's name comes from a large shoal, or rocky rapids, called the Chain of Rocks, which made that stretch of the Mississippi extremely dangerous to navigate.

[4] Because of a low-water dam built by the Army Corps of Engineers in the 1960s, little of the Chain of Rocks is visible today except during extreme low water conditions.

[5] After 1940, only a single impediment prevented the maintenance of a safe and reliable 9-foot (2.7 m) navigation channel on the Mississippi River from St. Paul, Minnesota, to New Orleans.

During this time, the bridge developed a reputation for crime and violence, including the April 1991 murder of sisters Julie and Robin Kerry.

In August 2021 the National Park Service announced the award of a $990,000 grant to Great Rivers Greenway to help develop and enhance the visitor area on the Missouri side of the bridge.