Cairo Flood Gate (Alexander County, Illinois)
Built on the plan of Gatum Dam on the Panama Canal and cost a little more than $11,000 dollars.
Flood Gate and Tunnel
Doesn't appear to be in use any longer

Cairo I-57 Bridge (Alexander County, Illinois)
Built 1978
Steel through arch bridge carrying I-57 over the Mississippi River at Cairo
Open to four lanes of traffic

Cairo Mississippi River Bridge (Alexander County, Illinois)
Built 1929; tolls removed 1954; rehabilitated 1983 and 2005
Cantilevered through truss bridge over the Mississippi River on US 60/62 between Birds Point, Missouri, and Cairo, Illinois
Open to two-lane traffic with a 40 ton weight limit

Cairo Ohio River Bridge (Alexander County, Illinois)
Built 1937; rehabilitated 1979
Cantilevered through truss over the Ohio River on US 51/60 between Cairo, Illinois and Wickliffe, Kentucky
Open to two-lane traffic

Cairo Railroad Bridge (Alexander County, Illinois)
Built 1949-52, replacing the original bridge
Through truss bridge over the Ohio River carrying the Illinois Central (now Canadian National Railway) in Cairo
Open to railroad traffic

First Cairo Railroad Bridge (Alexander County, Illinois)
Built 1889 under engineer George S. Morison; replaced during 1949-52
Lost through and deck truss bridge over the Ohio River carrying the Illinois Central Railroad in Cairo
Replaced by the current bridge, but reusing many of the piers