Manchac, Louisiana in the context of "Manchac Swamp Bridge"

The Manchac Swamp Bridge is a twin concrete trestle bridge near Manchac in the U.S. state of Louisiana. It carries Interstate 55 and U.S. Route 51 over the Manchac Swamp in Louisiana and represents a third of the highway's approximately 66 miles (106 km) in Louisiana.

With a total length of 22.80 miles (36.69 km), it is one of the longest bridges in the world over water, and is the longest bridge on the Interstate Highway System, and some claim it is the longest toll-free road bridge in the world.