The Arros (; ) is a right tributary of the Adour, in the Southwest of France. It is long. Name The name Arros is based on the root Arr- 'stone' and the suffix -os. Geography The Arros rises in the Baronnies of Pyrenees, southeast of Bagnères-de-Bigorre, below the Signal de Bassia (1 921 m). It flows north through a narrow valley defended by the castle of Mauvezin and the bastide of Tournay. It joins the Adour before it turn west, upstream from Riscle. Départements and towns Hautes-Pyrénées: Bourg-de-Bigorre, Tournay, Chelle-Debat Gers: Montégut-Arros, Villecomtal-sur-Arros, Plaisance. Main tributaries (L) Esqueda, from Banios (L) Luz, from Lies (L) Arredou, in Tournay (L) Arret Daban or Arret Devant, (L) Arret Darré, in Gonez (R) Bouès, from Capvern References Rivers of France Rivers of Gers Rivers of Hautes-Pyrénées Rivers of Occitania (administrative region)