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Stretching just under 24 miles (38.6 km), the Lake Pontchartrain Causeway is a marvel of modern engineering. Photo credit: Art Wager / Getty ImagesBridges rank among the most spectacular and awe-inspiring structures, captivating both visually and technically. They create a dramatic contrast with their natural surroundings, arching over vast waterways and seemingly defying the forces of gravity.
Examining the longest bridge in the U.S. reveals the immense complexity involved in its construction. These structures must not only remain stable but also support the weight of countless vehicles and passengers daily, fulfilling their critical role.
1. Lake Pontchartrain Causeway: 23.8 Miles (38.3 km)
Southern Louisiana boasts numerous lengthy bridges due to its expansive waterways and marshlands, which are impassable by conventional roads. The Lake Pontchartrain Causeway stands out as a colossal structure, featuring two parallel bridges that stretch across Lake Pontchartrain, linking Baton Rouge's eastern suburbs to New Orleans, Louisiana.
Constructed in 1956, this bridge held the record for the world's longest overwater bridge for many years. The Guinness Book of World Records recognized this achievement until China's Jiaozhou Bay Bridge surpassed it in 2011. Unlike the straightforward twin-span design of the Lake Pontchartrain Causeway, the Jiaozhou Bay Bridge employs a more intricate suspension bridge architecture.
To the east of the Lake Pontchartrain Causeway lies another lengthy, though less remarkable, bridge that traverses Lake Pontchartrain. The Norfolk Southern Lake Pontchartrain Bridge extends 5.8 miles (9.3 km) over water, offering Amtrak rail services to passengers traveling through southern Louisiana.
2. Manchac Swamp Bridge: 23 Miles (37 km)
A short distance west of the Lake Pontchartrain Causeway, another pair of parallel bridges nearly rivals its length.
True to its name, the Manchac Swamp Bridge spans 23 miles (37 km) of Louisiana's bayou wetlands, including a small section of Lake Maurepas. This remarkable highway bridge was completed in 1979.
3. Atchafalaya Basin Bridge: 18.2 Miles (29.3 km)
Another lengthy bridge in the bayou region, this 18-mile-long highway, also referred to as the Louisiana Airborne Memorial Bridge, links Lafayette and Baton Rouge while traversing the swampy terrain of the Atchafalaya Basin.
Constructed in 1973, the Atchafalaya Basin Bridge predates our previous entry by a few years.
4. Chesapeake Bay Bridge Tunnel: 17.6 Miles (28.3 km)
From an engineering perspective, the Chesapeake Bay Bridge Tunnel is one of the most remarkable bridges in the U.S., stretching 17.6 miles (28.3 km) from Virginia Beach to Cape Charles, Virginia, and the surrounding islands.
This expressway not only traverses water but also includes two 1-mile (1.6-km) underwater tunnels to enhance its durability. Originally opened in 1964, it underwent a major expansion in 1999.
5. Bonnet Carré Spillway Bridge: 11 Miles (17.7 km)
Constructed in 1972, this bridge lies just west of New Orleans, running parallel to Lake Pontchartrain on its northern side and the LaBranche wetlands to the south.
The 11-mile (17.7 km) Bonnet Carré Spillway Bridge derives its name from a critical flood control structure designed to protect New Orleans by diverting floodwaters during hurricanes or severe storms.
6. Louisiana Highway 1 Bridge: 8.3 Miles (13.4 km)
Situated at the southeastern edge of Louisiana, this 8.3-mile (13.4 km) bridge crosses Bayou Lafourche, providing access to some of the more isolated regions of the swamp. The Louisiana Highway 1 Bridge, completed in 2009, is among the newest structures on this list.
7. Jubilee Parkway: 7.5 Miles (12.1 km)
Positioned east of Mobile, Alabama, this 7.5-mile (12.1 km) bridge stretches across the northern part of Mobile Bay, connecting Alabama's southern coast and extending toward Florida.
This bridge is unique as it runs parallel to Battleship Parkway and even intersects with it midway. Opened in 1978, it was initially named "America's Junior Miss Byway" as part of a sponsorship deal with a local beauty pageant in Mobile.
8. San Mateo-Hayward Bridge: 7 Miles (11.3 km)
Traveling through California's Bay Area, San Francisco and its surrounding peninsula are accessible only via four major bridges:
- The Golden Gate Bridge, linking to Sausalito in the north
- The Bay Bridge, connecting to Oakland in the east
- The San Mateo-Hayward Bridge, located south of San Francisco and joining with Hayward to the east
- The Dumbarton Bridge, extending into Silicon Valley (further south of SF) and linking Redwood City and Palo Alto with Newark
The most famous and iconic of these is undoubtedly the Golden Gate Bridge at the city's northern edge. However, at 1.7 miles (2.7 km), it is far from the longest. That distinction belongs to the San Mateo-Hayward Bridge, which stretches just over 7 miles (11.3 km) across San Francisco Bay.
This direct route across the bay connects the San Francisco Peninsula with Fremont, Oakland, and stunning natural preserves in the region. Opened in 1967, the San Mateo Bridge quickly became California's longest bridge, a title it still holds today.
While the U.S. once held the title for some of the world's longest bridges during the 20th century, most of these records now belong to bridges in East Asia, particularly those constructed after 2000. The current world record for the longest bridge, which is unlikely to be surpassed soon, is held by China's Danyang–Kunshan Grand Bridge. This monumental structure supports a high-speed rail line spanning an impressive 100 miles (161 km) from Shanghai to Nanjing in Jiangsu province. Finished in 2010, it narrowly surpassed the length of another high-speed rail bridge in Taiwan. Other nations competing for the top spot include Japan, Thailand, and Bangladesh.
