Marie de Nemours, originally known as Marie d'Orléans-Longueville , was the daughter of Henri II d'Orléans, duc de Longueville.
Descended from Jean d'Orléans, illegitimate son of Louis I, Duke of Orléans, she was known as Mademoiselle de Longueville prior to her marriage.
The Dukes of Longueville had acquired the principality of Neuchâtel through marriage to a Swiss princess, Margravine Johanna of Baden-Hochberg-Sausensberg. The couple were married on 22 May 1657 at Trie. The dukes of Nemours were descendents of the Dukes of Savoy having settled in France in the sixteenth century, where they ranked as princes étrangers.
Her Savoyard nieces included Marie Jeanne, Duchess of Savoy and Marie Françoise, Queen of Portugal. She left some interesting memoirs, published by C. B. Petitot in the Collection complete des memoires (1819–1829). She was the muse for Jean Loret's Muse historique (1650, 1660, 1665), a collection of weekly gazette burlesque reporting on the news of Paris society and the court of Louis XIV in the form of letters to Marie d'Orléans-Longueville which are considered an early example of French journalism.
Her childless death in 1707, without close relatives, opened a conflict about her vast inheritance. For example, see Duke of Estouteville.