Lake Pontchartrain
Estuary in southeastern Louisiana, named in 1699.
Lake Pontchartrain is an estuary in southeastern Louisiana, United States, covering 630 square miles with an average depth of 12 to 14 feet. Named in 1699 by French explorer Pierre Le Moyne d'Iberville for Louis Phélypeaux, comte de Pontchartrain, it forms the northern boundary of New Orleans and is crossed by the Lake Pontchartrain Causeway, the longest continuous bridge over water in the world. As an estuary, its 'Lake' title is a misnomer due to its narrow passage to the open sea.
Quick Facts
- Location
- Louisiana
- Lake Type
- Estuary, saline
- Countries
- United States
- Length
- 40 mi
- Area
- 630 mi2
- Depth
- 12 -
- Max Depth
- 65 ft
- Elevation
- 1 ft
- Other Name
- fr · Lac Pontchartrain
Facts from the source article.
Lore & Background
Lake Pontchartrain was formed 4,000 to 2,600 years ago as the evolving Mississippi River Delta shaped its southern and eastern shorelines with alluvial deposits. Human habitation of the region began at least 3,500 years ago, with one recorded Indigenous name for the lake being Okwata ('wide water'). In 1699, French explorer Pierre Le Moyne d'Iberville renamed it after Louis Phélypeaux, comte de Pontchartrain, a minister under Louis XIV. The name Pontchartrain itself comes from a place in France where Phélypeaux's château was situated, thought to originate from a bridge crossing the river Mauldre on the ancient route from Lutèce to Chartres.
Reader's Guide
Lake Pontchartrain is significant as a major estuarine system and the core of the wider Pontchartrain Basin, a 10,000 square mile watershed spanning 16 Louisiana parishes and four Mississippi counties. Its location forms the northern boundary of New Orleans, and a portage between the lake and the Mississippi River was central to the city's founding in 1718. The lake's ecosystems have been stressed by decades of oil and gas drilling, logging of cypress swamps, saltwater intrusion, and pollution, leading to conservation efforts. The future of the lake depends on restoring annual spring floods to its wetlands and controlling urban sprawl on the north shore. The Lake Pontchartrain Causeway, the longest continuous bridge over water in the world, crosses the estuary. The lake's brackish water and small tidal changes support a complex mixture of herbaceous wetlands, though cypress swamps have been severely degraded by past logging. Conservation management aims to increase wetland productivity and maintain biological diversity to support an ecotourism industry.
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