Louis Phélypeaux, comte de Pontchartrain

Louis Phélypeaux (1643–1727), marquis de Phélypeaux (1667), comte de Maurepas (1687), comte de Pontchartrain (1699), known as the chancellor de Pontchartrain, was a French politician.

After serving as head of the Parlement of Brittany, he held office as Controller-General of Finances and as Navy Secretary and, from 1690, Secretary of State of the Maison du Roi.

Long considered a failure, his reputation has been reevaluated by recent historiography which has shown that, in a period of difficulty, he was a capable administrator of an immense department which had responsibility for the French Navy, trade, colonies, matters of religion, Paris, the royal household and for finances. He conducted a census of the population from 1693 onwards, the first since Vauban's of 1678. At court he was an opponent of Fénelon and the Quietists.

Nonetheless, his handling of the French Navy, a powerful force under Colbert and Seignelay, is criticised, and he is considered to be in part responsible for the defeat at the battles of Barfleur and La Hougue in 1692.

Phélypeaux served as Chancellor of France from 5 September 1699 to 1 July 1714. Historian François Bluche wrote that "he gave the Chancellor's office an importance and authority not seen since the early years of Pierre Séguier." Saint-Simon painted a flattering portrait of Phélypeaux in his diaries, and his discretion was appreciated by Louis XIV.

He was made clerk of the prestigious Order of the Holy Spirit in May 1700.

In 1668 he married Marie de Maupeou. They had one son, Jérôme Phélypeaux (1674–1747), comte de Pontchartrain.

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. He had found it difficult to reconcile his religious beliefs with those of the increasingly authoritarian Louis XIV. He retired to an Oratorian institution where he died in 1727.

Lake Pontchartrain in Louisiana was named after him as well as the historic Hotel Pontchartrain in New Orleans, as was Fort Pontchartrain du Détroit in Michigan (the site of modern-day Detroit) and Detroit's historic Hotel Pontchartrain. In addition, Île Philippaux and Isle Pontchartrain which appear on early maps of Lake Superior are believed to have been named after him. Neither island, it was later determined, actually existed. They are thought to have been added to maps by French explorers hoping that Phélypeaux would be inspired to provide more funds to explore the area.