Saint-Mesmin (French pronunciation: [sɛ̃ mɛmɛ̃]) is a commune in the Vendée department in the Pays de la Loire region in western France.

In 1179, the names of the churches of Saint-Mesmin-le-Vieux « ecclesiam Sancti Maximini veteris » and Saint-André-sur-Sèvre « ecclesiam Sancte Andree super separim » appear on a list among 127 other churches, possessions confirmed in a papal bull of Pope Alexander III to the abbey of Saint-Jouin-de-Marnes, the Diocese of Poitiers.

In 1360, at the beginning of the century of conflict between the Plantagenets and the Capetians, which partly took place in Poitou, Normandy and Aquitaine, during the Hundred Years' War which opposed the English and the French, Jehan de Montfaucon, on March 20, is said knight and lord of the land of Saint-Mesmin, and Le Terrier, in the municipality of Mouilleron-en-Pareds, bailiwick of Vouvant and Mervent.

Fortification for the war, but also for the purpose of repelling the idle mercenaries, in times of peace, who plunder in the countryside, raping and peddling diseases in organized gangs, waiting to be at the service of a military army.

In 1755, Alexis-Françoise Petit married Messire Jacques-Rene-Francois-Marie de Vasselot, knight and lord, marquess dAnne-Marie.

About forty Vendéens led by Louis Péault, sergeant, gamekeeper of the Marquisate of Saint-Mesmin, attack a Republican detachment comprising 250 men commanded by Adjutant General Cortez.

The forty or so Vendeans were taken to la Chataigneraie, where the chief of staff ordered Bonnaire to assemble a military council to try them and shoot them, despite the promise of life saved.

General Hoche, commander-in-chief of the Western troops, warned of the incident, demanded and obtained from his subordinates the respect of the terms of the surrender.