Is America’s Longest Bridge at Risk? the Shocking Scale of Massive Water Crossings
By Maya Lin-Takahashi
The sheer scale of these spans becomes clear when comparing lengths, design types, and daily vehicle burdens across the nation's most critical water crossings.
| Structure | Length (Miles / km) | Primary Structural Type | Year Opened | Location |
|---|---|---|---|---|
| Lake Pontchartrain Causeway | 23.83 mi (38.35 km) | Prestressed Concrete Trestle | 1956 / 1969 | Mandeville, Metairie, LA |
| Manchac Swamp Bridge | 22.80 mi (36.69 km) | Concrete Pier Viaduct | 1979 | St. John the Baptist Parish, LA |
| Atchafalaya Basin Bridge | 18.20 mi (29.29 km) | Elevated Concrete Highway | 1973 | Baton Rouge, Lafayette, LA |
| Chesapeake Bay Bridge-Tunnel | 17.60 mi (28.32 km) | Trestle, Island & Tunnel Complex | 1964 / 1999 | Virginia Beach, Cape Charles, VA |
| I-10 Bonnet Carré Spillway Bridge | 11.00 mi (17.70 km) | Concrete Trestle Over Spillway | 1972 | St. Charles Parish, LA |
Outside of the Gulf South, the Chesapeake Bay Bridge-Tunnel in Virginia offers the most complex design among major water crossings. Rather than maintaining an uninterrupted bridge deck, it drops beneath two major Atlantic shipping channels via mile-long immersed tube tunnels. This setup protects naval vessel traffic heading into Norfolk while carrying over 4 million vehicles annually across open open-ocean conditions.
Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.
