Pallars is a historical and natural region of Catalonia. Located in the Pre-Pyrenees and Pyrenees area, most of its territory is mountainous. The Noguera Pallaresa river is named after this region. Geography. The physiography of the Pallars natural region includes the Noguera Pallaresa river basin with its tributaries. The region encompasses as well as the mountain ranges spanning the Pyrenees and Pre-Pyrenees area that surround the basin until the Serra del Montsec which forms the limit of the Pallars at its southern end. Municipalities.
https://en.wikipedia.org/wiki/Pallars