POITOU, one of the old provinces of France, which also formed one of the great military governments of the kingdom, was bounded N. by Brittany, Anjou, and Touraine; S. by Angoumois and Aunis; E. by Touraine, Berri, and Marche; and W. by the ocean. It was divided into Lower Poitou, which corresponded to the modern department of La Vendée, and Upper Poitou, now split into the departments of Deux-Sèvres and Vienne. The principal towns in Upper Poitou were Poitiers the capital, Mirebeau, Châtellerault, Richelieu, Loudun, Thouars, Mauléon, Parthenay, Niort, <fcc.; and in Lower Poitou Fontenai-le-Comté, Maillezais, Luçon, and Roche-sur-Yon. île d'Yeu or Île-Dieu and Noirmoutier belonged to the province. Ecclesiastically Poitou was distributed among the dioceses of Poitiers, Luçon, and La Rochelle; for the administration of justice, it was attached to the parlement of Paris.

Poitou (Poictou, Pictavia) takes its name from the Pictones or Pictavi, a Gallic nation mentioned by Caesar, Strabo, and Ptolemy, and described by Strabo as separated from the Namnetes on the north by the Loire. It formed part of the territory known as Aquitania (g.u). For the history see Poitiers.