The second largest salt-water lake in the United States, Lake Pontchartrain is actually an estuary with a mixture of salt and fresh water.
The lake still has fluctuations in water level due to the tide. Local groups work to raise money with the annual Back to the Beach Festival to preserve the water quality of the lake.
The lake was named after Louis Phelypeaux, comte de Pontchartrain, the French Minister of the Marine during the reign of King Louis XIV, for whom Louisiana is named.
