Amazing nature of Florida Keys, Marathon island, Seven Mile Bridge road. Endless way. USA.

11 Longest Bridges in the United States

Faced with the crushing reality of impassable waters, Americans have refused defeat by crafting engineering marvels to cross the impossible. These bridges enable cities and states to operate efficiently and quickly for civilians and industries. Technically, the United States has somewhere in the neighborhood of 617,000 bridges, but the following eleven are the longest in the land. 

11 Longest Bridges in the US

  1. Lake Pontchartrain Causeway - 23.83 miles
  2. Manchac Swamp Bridge - 23 miles
  3. Louisiana Airborne Memorial Bridge - 18.2 miles
  4. Chesapeake Bay Bridge-Tunnel - 17.6 miles
  5. Bonnet Carré Spillway Bridge - 11 miles
  6. Louisiana Highway 1 Bridge - 8.26 miles
  7. Jubilee Parkway - 12.87 miles
  8. San Mateo-Hayward Bridge - 11.27 miles
  9. Seven Mile Bridge - 6.7 miles
  10. General W.K. Wilson Jr. Bridge - 9.78 miles
  11. Norfolk Southern Lake Pontchartrain Bridge - 5.8 miles

1. Lake Pontchartrain Causeway - 23.83 miles

 Lake Pontchartrain Causeway traffic on March 27, 2009 in New Orleans, via pisaphotography / Shutterstock.com
 Lake Pontchartrain Causeway traffic on March 27, 2009 in New Orleans, via pisaphotography / Shutterstock.com

The country's biggest kahuna stretches a colossal 23.83 miles (38.35 kilometers) across Lake Pontchartrain, in Southeastern Louisiana (a common site for the nation's longest bridges). The Southbound lane of the Lake Pontchartrain Causeway, or simply "The Causeway," was built by The Louisiana Bridge Company in 1956, and then the parallel addition to this juggernaut of engineering was added in 1969, effectively connecting the communities of Metairie and Mandeville. The Causeway held the Guinness World Record for longest bridge over water until 2011, when China's Jiaozhou Bay Bridge sort of took the crown. Due to stubborn semantics, there are now two categories of water-crossing bridges. The Causeway regained its title, but nowadays has a "continuous" qualifier in there for good measure. 

2. Manchac Swamp Bridge - 23 miles

The Manchac Swamp Bridge in Louisiana, via Melanie Commander Thibodaux
The Manchac Swamp Bridge in Louisiana, via Melanie Commander Thibodaux 

Coming in at a close second is Louisiana's Manchac Swamp Bridge, which spans a startling 23 miles (37.01 kilometers) over Manchac Swamp (which is reportedly haunted), in Southeastern Louisiana. This twin concrete trestle construction is also one of the world's longest bridges over water, one of the longest toll-free bridges, and finally, one of the longest freeway bridges. The Manchac Swamp Bridge, built in 1979, makes up roughly one-third of Interstate 55/U.S. Route 51, and connects the locales of St. John the Baptist Parish and Tangipahoa Parish.  

3. Louisiana Airborne Memorial Bridge - 18.2 miles

Atchafalaya Basin Bridge, also called the Louisiana Airborne Memorial Bridge, stretches over the water of Atchafalaya Basin and runs from Lafayette to Baton Rouge, Louisiana
Atchafalaya Basin Bridge, also called the Louisiana Airborne Memorial Bridge, stretches over the water of Atchafalaya Basin and runs from Lafayette to Baton Rouge, Louisiana

Louisiana grabs all three spots on the long-bridge podium. The Louisiana Airborne Memorial Bridge is the formal designation, but this 18.2-mile (29.29-kilometer) boundary-breaker is more commonly known by its original title: the Atchafalaya Basin Bridge. As the name suggests, this bridge crosses the Atchafalaya Basin, which is actually the largest swamp/wetland in the country. Construction on this four-lane, suspended segment of Interstate 10, began in 1971 and finished two years later, thereby connecting the cities of Baton Rouge (Louisiana's capital) and Lafayette. The Louisiana Airborne Memorial Bridge is unique in that it is a set of parallel bridges for much of its length, merging into a singular structure at the crossing of Whiskey Bay Pilot Channel and the Atchafalaya River. 

4. Chesapeake Bay Bridge-Tunnel - 17.6 miles

The light traffic on Chesapeake Bay Bridge Tunnel in the summer, via Khairil Azhar Junos / Shutterstock.com
The light traffic on Chesapeake Bay Bridge Tunnel in the summer, via Khairil Azhar Junos / Shutterstock.com

The Chesapeake Bay Bridge-Tunnel seems to defy physics, and also classification, which is why exact measurements vary depending on who you ask. But according to the bridge's official website, the CBBT covers a total of 17.6 miles (28.32 kilometers) both above and below Chesapeake Bay (there are two, one-mile tunnels to break up the journey). This eclectic marvel of engineering connects Southeastern Virginia communities of Delmarva and Hampton Roads and the aberrant East Coast with the rest of the state's mainland. The first two lanes of the CBBT opened in 1964, alleviating the strain on the commuter ferries, and then in 1999 the bridge was largely dualized, with four lanes now operating above ground, while the tunnels still charge ahead with two. 

5. Bonnet Carré Spillway Bridge - 11 miles

Bonnet Carre Spillway Bridge in Louisiana, via
Bonnet Carre Spillway Bridge in Louisiana, via I-10 Bonnet Carré Spillway Bridge - Super Engineering Website (reduper.com)

Louisiana is back on the board to round out the top five. The Bonnet Carré Spillway, or Bonnet Carré Floodway, covers 11 miles (17.7 kilometers) above Lake Pontchartrain, Bonnet Carré Spillway (of course), and the LaBranche Wetlands. The bridge, opened in 1972, runs atop this flood-mitigation structure, once again forwarding the path of Interstate 10, this time as it connects St. Charles Parish and portions of St. John the Baptist and Jefferson Parishes, in the Southeastern segment of the state. When needed, this benevolent spillway diverts the waters of the Mississippi River into Lake Pontchartrain, thereby averting disaster for the historically flood-prone city of New Orleans

6. Louisiana Highway 1 Bridge - 8.26 miles

Louisiana Highway 1 Bridge, via Oil spill recovery cash finances Louisiana’s coastal projects but will disappear by 2032 - Louisiana Illuminator (lailluminator.com)

The Louisiana Highway 1 Bridge, or the Gateway to the Gulf Expressway crosses the Bayou Lafourche and some other marshes in the far Southeast end of The Pelican State. Completed in 2009, this extensive toll bridge (one of the longest in the land) stretches for 8.26 miles (13.29 kilometers) throughout Lafourche Parish and makes up a segment of Louisiana Highway 1 (in case that wasn't clear!) that connects Leeville to Port Fourchon. 

7. Jubilee Parkway - 12.87 miles

Jubilee parkway on Mobile Bay at sunset from Daphne, Alabama in July of 2022
Jubilee parkway on Mobile Bay at sunset from Daphne, Alabama in July of 2022

Southern Alabama's Jubilee Parkway takes Interstate 10 motorists for an 8-mile (12.87-kilometer) ride across the Northern portion of Mobile Bay, and parts of Baldwin and Mobile Counties. Built in 1978 and originally called America's Junior Miss Byway, this set of adjacent viaduct bridges (two lanes a piece) runs roughly parallel to the Battleship Parkway, linking Blakely Island and Spanish Fort/Daphne. There have been ongoing discussions for over twenty years about expanding the Jubilee Parkway to eight lanes, as well as rerouting it in order to skip the traffic-ridden George Wallace Tunnel. 

8. San Mateo-Hayward Bridge - 11.27 miles

Aerial view from an airplane of San Mateo Hayward bridge across the San Francisco Bay and Foster City in San Mateo County, California
Aerial view from an airplane of San Mateo Hayward bridge across the San Francisco Bay and Foster City in San Mateo County, California

This L-shaped bridge in coastal California runs for 7 miles (11.27 kilometers) across San Francisco Bay, thereby connecting the San Francisco Peninsula with the Eastern Gulf. The San Mateo-Hayward Bridge, commonly referred to as the San Mateo Bridge, for short, became (and still remains) California's longest bridge when it opened in 1967. The Western terminus is Foster City, in San Mateo County, while the East side rolls into Hayward, a city in Alameda County. The creative shape was designed by the California Department of Transportation, and constructed by Murphy Pacific Bridge Builders and Pomeroy-Gerwick Steers in 1967, with a Westbound bridge added in 2002. 

9. Seven Mile Bridge - 6.7 miles

7 Seven Miles bridge. Endless road, Aerial view, Florida Keys. USA.
7 Seven Miles bridge. Endless road, Aerial view, Florida Keys. USA.

Seven miles? More like 6.7 miles (10.78 kilometers)! The Seven Mile Bridge is a cherished shooting location for Hollywood. Scenes from True Lies, Licence to Kill, and 2 Fast, 2 Furious capture action stars racing from the city of Marathon to Little Duck Key (or vice versa), in the Florida Keys. The modern bridge (built in 1982) funnels two lanes of the US 1 highway over the Moser Channel, while the older, narrower bridge (originally a railroad bridge, built in 1912) is still going strong and is open only to pedestrians and cyclists.

10. General W.K. Wilson Jr. Bridge - 9.78 miles

The General W.K. Wilson Jr. Bridge (Dolly Parton Bridge) near Mobile, Alabama
The General W.K. Wilson Jr. Bridge (Dolly Parton Bridge) near Mobile, Alabama

Bringing it back to the Alabama counties of Mobile and Baldwin, the General W.K. Wilson Jr. Bridge (nicknamed the "Dolly Parton Bridge") taps out at 6.08 miles (9.78 kilometers). The weathering steel arches make this Mobile-Tensaw River Delta-spanning bridge pop against the green surroundings. Completed in 1980, General W.K. Wilson Jr. Bridge, named after the Chief of Engineers with the United States Army Corps/long-term Mobile resident, is a memorable, four-lane (split between two parallel bridges) section of Interstate 65. 

11. Norfolk Southern Lake Pontchartrain Bridge - 5.8 miles

Norfolk Southern Lake Pontchartrain Bridge
Norfolk Southern Lake Pontchartrain Bridge, via Norfolk Southern Lake Pontchartrain Bridge - longest in the world (nolahistoryguy.com)

Switching it up a bit to cap things off (while simultaneously ending where we began), the Norfolk Southern Lake Pontchartrain Bridge supports the Norfolk Southern Railway Amtrak, rather than commuting cars, as it crosses the titular lake in Southeastern Louisiana. Even though it ranks 11th in the country, overall, this 5.8-mile (9.3-kilometer) piece of impressive infrastructure was built way back in 1884, and takes the crown for longest railroad bridge in the United States, and the longest water-spanning railroad bridge in the world. 

These eleven marvels of modern innovation are not only logistical saviors and time-savers, they are memorable modes of transportation. All too often a bridge crossing gives a brief, beautiful view, and the slightly unnerving, but also exhilarating sensation of floating, only to kick you back out onto some boring highway or country road. But the longest bridges in the U.S. extend the fun for miles upon miles. Thanks science!  

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