The Keokuk Bridge, also known as the Keokuk Municipal Bridge, carries a double deck single track railway and highway bridge across the Mississippi River in the USA between Keokuk, Iowa and Hamilton, Illinois, just downstream of Mississippi Lock and Dam number 19. It was designed by Ralph Modjeski and constructed 1915–1916 on the piers of its predecessor that was constructed in 1869–1871.
Following the completion of the Keokuk-Hamilton Bridge, the upper deck of this bridge, on the Keokuk side, was converted to an observation deck to view the nearby lock and dam; this deck is no longer used for road traffic, but is still used for rail traffic. The bridge was originally owned by the Keokuk & Hamilton Bridge company, but following financial problems in the 1940s, the bridge was given to the City of Keokuk in late 1948.
The bridge was originally the western terminus of the Toledo, Peoria & Western Railroad. Today, it serves the Keokuk Junction Railway with an occasional train crossings for interconnection and river terminal services. Only the Keokuk side of the highway bridge has been converted, the bridge's upper highway deck is abandoned. The river traffic (barges and boats) have the right-of-way, so the swing section remains open until a train needs to cross the river.
It is documented in the Library of Congress Historic American Engineering Record as survey number IA-3.