La Bastide-sur-l'Hers is a French commune in the Ariège department in the Occitanie region of southwestern France.The inhabitants of the commune are known as Bastidhersois or Bastidhersoises.GeographyLa Bastide-sur-l'Hers is located some 28 km south-east of Pamiers and 3 km north-east of Lavelanet. Access to the commune is by the D620 road from Laroque-d'Olmes in the north-west which goes east through the commune and the village and continues east to Le Peyrat. The D16 comes from L'Aiguillon in the south and passes north inside the eastern border of the commune to the village then continues north to join the D28A south of Léran. A former railway line now a walking trail passes through the commune from west to east just north of the village. The commune has two large belts of forest across the centre and south with most of the rest of the commune farmland.The Hers river flows from the south forming the south-eastern border before passing through the village and continuing east to eventually join the Ariège at Cintegabelle. The Ruiseeau des Écrevisses forms the southern border of the commune as it flows east to join the Hers. The Ruisseau de Pépoulant also flows east across the commune a little further north and joins the Hers.