The Pietrosul (Hungarian: Köves-Somlyó or Köves-Somlyó-patak; Hungarian pronunciation: [ˈkøvɛʃʃomjoː]) is a left tributary of the Mureș in Romania.[1][2] It flows into the Mureș between Joseni and Remetea. Its length is 13 km (8.1 mi) and its basin size is 40 km2 (15 sq mi).[2]