Municipality of Loire-Atlantique, in the Pays de la Loire region, Petit-Mars takes place only about twenty kilometers from Nantes, in the heart of historic Brittany. It is located in the Erdre valley, not far from Carquefou, Sucé-sur-Erdre and Ligné.
Petit-Mars originates in the Gallo-Roman era, thanks to the clearing of the forest of Mars which was originally on the marshes. However, it was not until the middle of the 17th century to see the creation of the new town we know today. It then presented significant development because of its proximity to Nantes, taking advantage of its economic boom to expand.