Manchac Swamp Bridge

The Manchac Swamp Bridge is a twin concrete trestle bridge[1] in the U.S. state of Louisiana. With a total length of 22.80 miles (36.69 km)[2][3] it is one of the longest bridges in the world over water and is the longest bridge on the Interstate Highway System. Some claim it is the longest toll-free road bridge in the world.[4] The bridge carries Interstate 55 and U.S. Route 51 over the Manchac Swamp in Louisiana, and represents one-third of the highway's approximately 66 miles in Louisiana. Opening in 1979,[1] its piles were driven 250 feet (76 m) beneath the swamp and with the cost of the span being $7 million per mile to complete.[5]

Manchac Swamp Bridge
Coordinates	30.302946°N 90.405807°W
Carries	I-55 / US 51
Crosses	Manchac Swamp
Locale	St. John the Baptist Parish / Tangipahoa Parish, Louisiana, USA
Other name(s)	I-55 Manchac Swamp Crossing
Maintained by	LA DOTD
Characteristics
Total length	22.8 miles (36.7 km)
Width	95 m
History
Opened	1979[1]
Location

See also

•  Transport portal
•  Engineering portal
•  United States portal
• List of bridges in the United States
• List of longest bridges

References

1. Melaragno, Michele G. (1998). Preliminary Design of Bridges for Architects and Engineers. CRC Press. p. 377. ISBN 978-0-8247-0184-0. Retrieved June 20, 2010.
2. "Manchac Swamp Bridge". Atlas Obscura. Retrieved 2019-05-02.
3. "Manchac Swamp Bridge". www.dangerousroads.org. Retrieved 2019-05-02.
4. "Longest Bridges in North America". WorldAtlas. Retrieved 2019-05-02.
5. Loh, Jules (June 8, 1977). "Louisiana 'oasis' is cypress-paneled". The Tuscaloosa News. Tuscaloosa, AL. p. 6. Retrieved June 20, 2010.