Deva (Romanian pronunciation: [ˈdeva] ; Hungarian: Déva, Hungarian pronunciation: [ˈdeːvɒ]; German: Diemrich, Schlossberg, Denburg; Latin: Sargetia; is a city in Romania, in the historical region of Transylvania, on the left bank of the river Mureș. It is the capital of Hunedoara County.

The Mureș or Maros is a 789-kilometre-long (490 mi) river in Eastern Europe. Its drainage basin covers an area of 30,332 km2 (11,711 sq mi). It originates in the Hășmașu Mare Range in the Eastern Carpathian Mountains, Romania, rising close to the headwaters of the river Olt, and joins the Tisza at Szeged in southeastern Hungary. In Romania, its length is 761 km (473 mi) and its basin size is 27,890 km2 (10,770 sq mi).