The Lotru is a right tributary of the Olt river in Romania.[1][2] Its source is in the Parâng Mountains. It feeds the Vidra, Malaia and Brădișor reservoirs. It flows into the Olt in Golotreni, near the town of Brezoi.[3] It flows through the municipalities of Voineasa, Malaia and Brezoi. Its length is 83 km.