Louis Phélypeaux (1643–1727), marquis de Phélypeaux (1667), comtede Maurepas (1687), comtedePontchartrain (1699), known as the chancellor dePontchartrain, was a French politician.
He resigned in 1714 for having failed to affix the seals to the decree of 5 July 1714, condemning a document by the Bishop of Metz, Henri-Charles de Coislin, as contrary to the papal bull Unigenitus.
Lake Pontchartrain in Louisiana was named after him, as was Fort Pontchartrain du Détroit in Michigan (at modern Detroit).
Lake Pontchartrain is an estuary which connects with the Gulf of Mexico via Rigolets strait (known locally as "the Rigolets") and Chef Menteur Pass into Lake Borgne, and therefore experiences small tidal changes.
In 1699, French explorer Pierre Le Moyne d'Iberville, renamed it Pontchartrain after Louis Phélypeaux, comtedePontchartrain, the French Minister of the Marine, chancellor of France and minister of finance during the reign of France's "Sun King," Louis XIV, for whom Louisiana is named.
The Lake Pontchartrain Causeway was constructed in the 1950s and 1960s, connecting New Orleans (by way of Metairie) with Mandeville and bisecting the lake in a north-northeast line.