Saint-PerreuxSaint-Perreux is a commune in the Morbihan department of Brittany in north-western France. It was named after the Welsh monk, Saint Petroc.WWW Official SiteGeographyThe river Arz forms most of the commune's western and south-western borders, then flows into the Oust, which forms the commune's eastern border.DemographicsInhabitants of Saint-Perreux are called in French Perrusiens or Perreusiens.