The Olt (Romanian and Hungarian; German: Alt; Latin: Aluta or Alutus, Turkish: Oltu, Ancient Greek: Ἄλυτος Alytos) is a river in Romania. It is 615 km (382 mi) long, and its basin area is 24,050 km (9,290 sq mi). It is the longest river flowing exclusively through Romania. Its average discharge at the mouth is 174 m/s (6,100 cu ft/s). It originates in the Hășmaș Mountains of the eastern Carpathian Mountains, near Bălan, close to the headwaters of the river Mureș. The Olt flows through the Romanian counties of Harghita, Covasna, Brașov, Sibiu, Vâlcea, and Olt. The river was known as Alutus or Aluta in Roman antiquity. Olt County and the historical province of Oltenia are named after the river.
Sfântu Gheorghe, Râmnicu Vâlcea and Slatina are the main cities on the river Olt. The Olt flows into the Danube river near Turnu Măgurele.