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
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