From the record
“The Chain of Rocks Bridge spans the Mississippi River on the north edge of St. The eastern end of the bridge is on Chouteau Island, while the western end is on the Missouri shoreline.”
Wikipedia article Chain of Rocks Bridge, CC BY-SA 4.0.
One of 40 National Register listings published here for Madison County · listed in 2006 · category: Structure.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service

