Pontchartrain, Lake

Shallow, brackish body of water that lies north of New Orleans and the Mississippi delta, in the southeast of Louisiana. Lake Pontchartrain is 66 km/41 mi long by 40 km/25 mi wide (at its broadest point), but is nowhere more than 5 m/16 ft deep. The total surface area is about 1,632 sq km/630 sq mi. It has long been an important source of seafood for New Orleans, and has many urban and country resorts around its shores.

The lake is connected with Lake Maurepas to the west and Lake Borgne (and inlet of the Gulf of Mexico) to the east. Most of its southeastern shore is occupied by New Orleans and Metairie, and is protected by a seawall. A 16 km/10 mi-long bridge crosses the lake's eastern end, between New Orleans and Slidell. The Lake Pontchartrain Causeway, which runs across the centre of the lake between Metairie and Covington, has a double carriageway; covering a distance of at 39 km/24 mi, it is the longest such structure in the world; drivers using it are out of sight of land for about 13 km/8 mi.