Discover the 5 Longest Bridges in the United States

From the George Washington Bridge in New York City to San Francisco’s Golden Gate, you would be hard-pressed to crawl from one end of the country to the other without crossing a bridge or two. Bridges come in all different types. Some, like the Golden Gate and GW, are suspension bridges. Others, like the New River Gorge Bridge, are arch bridges.

In the United States, bridges span rivers, bays, gorges, lakes, and other geographical features. Some are tiny and only a few feet long. For example, the Pennypack Creek Bridge in Northeast Philadelphia is only 73 feet. Whether it’s the 5,989-foot Brooklyn Bridge or the 4.1-mile Sunshine Skyway Bridge in Florida, many of America’s bridges are technological marvels. Read on to discover the five longest bridges in the United States.

1. Lake Pontchartrain Causeway Bridge, Louisiana

At 24 miles, the Lake Pontchartrain Causeway Bridge in Louisiana is by far the longest bridge in the U.S. and, according to Guinness World Records the longest continuous bridge over water. And get this: it took just 14 months to build.

The idea of building a bridge over Lake Pontchartrain, a 40-mile wide inland saltwater estuary that covers 630 square miles, was first proposed in the middle of the 20^th century. At the time, the population of New Orleans was growing. But to get to the north shore of the lake was a time-consuming drive that could take hours.

On August 30, 1956, the ribbon was cut on the Lake Pontchartrain Causeway Bridge, linking New Orleans on the south shore to the more rural communities to the north. Commuters instantly loved the ease with which they could travel. Those working in the Big Easy had their commuting time cut while new businesses opened on both sides of the span.

Two Spans in One

The causeway is actually two bridges as the southbound and northbound lanes parallel one other. Some 9,500 concrete pilings support the 24-mile span. Construction was completed in near record time as engineers utilized a type of assembly-line production seen mostly in factories. The first span is the original bridge, which now carries traffic to the south. It is supported by 54-inch diameter hollow pilings. The massive pilings were twice the diameter of the standard solid pilings, creating a super-strong foundation.

The Louisiana Bridge Co. built a concrete plant on the shore of Lake Pontchartrain. At the plant, workers built the different parts of the bridge and floated them down to the construction site. Each individual component, whether a piling or deck, was interchangeable, much like a car factory’s assembly line. This sped construction along. In fact, the original span took only 14 months to build. Construction crews finished the second span, which links Metairie to Mandeville, in 1969.

2. Manchac Swamp Bridge, Louisiana

U.S. Highway 51 is a 1,277-mile expressway that runs from Louisiana to Wisconsin. Located just west of New Orleans, at the junction of Interstate 10, the most southern portion of Route 51 crosses the Manchac Swamp. The Manchac Swamp Bridge is 22.8 miles long and transports about 2,250 drivers a day.

The Manchac Swamp Bridge is the longest span of the country’s Interstate system. Workers built the twin concrete trestle bridge connecting St. John the Baptist Parish and Tangipahoa Parish in 1979.

While the bridge’s design is rather simplistic, the swamp it crosses is supposedly one of the most haunted areas in Louisiana. That’s saying a lot in a state known for its ghost stories. If you believe in such things, the “Ghost Swamp,” as many locals call Manchac, is allegedly haunted by a voodoo priestess. Her name was Julie Brown, and legend has it she put a curse on the nearby town of Frenier in 1915. A hurricane leveled the town on the day she died, killing many people, most of whom attended her funeral. Supposedly, these poor mourners were buried in a mass grave in the swamp.

3. Atchafalaya Basin Bridge, Louisiana

The third longest bridge in the United States is also in the Pelican State. Slightly more than 18 miles long, the Atchafalaya Basin Bridge, also known as the Louisiana Airborne Memorial Bridge, is a four-lane parallel span on Interstate 10 that crosses the Atchafalaya Basin, linking Baton Rouge to Layafette. The bridge opened in 1973.

The basin’s soil is thick with mud, not exactly a good base on which to build a heavy structure. At various points along the route, work crews had to dig more than a hundred feet before striking a more suitable base on which to lay the bridge’s pilings.

Prefab Wonder

Taking a page from the construction of the Lake Pontchartrain Causeway, the Atchafalaya Bridge was also prefabricated. After clearing a 300-foot-wide canal, parts of the bridge sailed down Lake Pontchartrain, through New Orleans, up the Mississippi River, and finally down the Intracoastal Waterway to the construction site. The trip took four days to make the 250-mile journey.

Workers then planted the pilings and expertly caped each. Cranes then hoisted each 265-ton-prefab slab one at a time onto the capped pilings, connecting them with steel and concrete. Workers worked tirelessly to lay 350 feet of roadway each day. Once the bridge opened, it substantially cut the drive time from New Orleans to Baton Rouge. The causeway is part of a major thoroughfare that not only transports people but also goods.

4. Chesapeake Bay Bridge-Tunnel, Virginia

Many consider the Chesapeake Bay Bridge-Tunnel, officially known as the Lucius J. Kellam Jr. Bridge-Tunnel, an engineering marvel. The bridge-tunnel system is 17.6 miles long and includes areas where ships can pass. Located in Virginia, where the Chesapeake meets the Atlantic Ocean, the Bay Bridge-Tunnel rises and dips over and under the water, supported by humanmade islands.

Engineers had to keep many things in mind when designing the system. Chief among them was building a bridge and tunnel system that would not impede the area’s shipping lanes. Engineers designed the tunnels deep beneath those lanes. To make construction easier, workers built four artificial islands that allow the roadway to enter the tunnels. The Thimble Shoal Tunnel is 15,738 feet long, while the Chesapeake Channel Tunnel is 5,423 feet. Twenty-five-ton boulders surround each island as protection against the raging ocean.

Construction of the original bridge tunnel began in 1958 and ended six years later. In 1995, workers began constructing a parallel bridge. It opened in 1999. In 2017, workers began construction on a new two-lane tunnel that will carry southbound traffic.

5. Louisiana Highway 1 Bridge, Louisiana

Known as the Gateway to the Gulf Expressway, the Louisiana Highway 1 Bridge is an 8.26-mile concrete trestle bridge connecting Leeville to Port Fourchon. Highway 1 is the only land route to Port Fourchon and Grand Isle and one of the longest highways in the state. The bridge opened in 2009. Plans include expanding the bridge to Golden Meadow, farther north.

The Highway 1 Bridge is a work in progress. The first phase of the plan included building an 11-mile elevated expressway from Leeville to Port Fourchon. Engineers tackled this phase in two parts, completing the first stage in 2009. Crews finished the second stage in 2011.

The state is currently working on the second phase of the plan, which includes extending the bridge eight miles to Golden Meadow. When completed, this segment will have better evacuation routes during hurricanes and accessibility for recreational fishing.