Lake Pontchartrain

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Lake Pontchartrain
Sentinel-2 image
Lake Pontchartrain Show map of Louisiana Lake Pontchartrain Show map of the United States
Map
Location	Louisiana
Coordinates	30°11′20″N 90°06′05″W / 30.18889°N 90.10139°W / 30.18889; -90.10139
Lake type	Estuary, saline
Basin countries	United States
Max. length	40 mi (64 km)
Max. width	24 mi (39 km)
Surface area	630 sq mi (1630 km2)
Average depth	12–14 ft (3.7–4.3 m)
Max. depth	65 ft (20 m)
Surface elevation	1 ft (0.30 m)

Lake Pontchartrain (/ˈpɒntʃətreɪn/ PON-chə-trayn)^[1] is an estuary located in southeastern Louisiana in the United States. It covers an area of 630 square miles (1,600 km²) with an average depth of 12 to 14 feet (3.7 to 4.3 m). Some shipping channels are kept deeper through dredging. It is roughly oval in shape, about 40 miles (64 km) from west to east and 24 miles (39 km) from south to north.

In descending order of area, the lake is located in parts of six Louisiana parishes: St. Tammany, Orleans, Jefferson, St. John the Baptist, St. Charles, and Tangipahoa. The water boundaries were defined in 1979 (see list of parishes in Louisiana).

The lake is crossed by the Lake Pontchartrain Causeway, the longest continuous bridge over water in the world.^[2] A power line also crosses the lake. Its towers stand on caissons in Lake Pontchartrain, and its length can be used to visually demonstrate the curvature of the Earth.^[3]