The Norfolk Southern Lake Pontchartrain Bridge is a bridge that carries a single-track of Norfolk Southern rail line between Slidell and New Orleans, Louisiana. At 5.8 miles (9.3 km) long, it is the longest railroad bridge in the United States and likely the longest rail bridge over water in the world. The Huey P. Long Bridge in nearby Jefferson Parish has sometimes been given that title, but at about 4.4 miles (7.1 km), that bridge is considerably shorter than the Norfolk Southern bridge.
The bridge is heavily used by Norfolk Southern freight trains. In addition, Amtrak's Crescent passenger train crosses the bridge once daily in each direction.