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The Jiu river is formed from the East Jiu, which source of water is in the Parang Mounatains and the West Jiu which flows from the Retezat-Godeanu Mountains. The East and West Jiu unite in the Petrosani depression near the Livezeni city. The Jiu passes though the historical province Oltenia and flows in the Danube near the Bechet city.



Total length: 331 km (from the West Jiu spring)
Reservoir area: 10.070 km²

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In the Sub-Carpathian depression Targul Jiu, the Jiu river receives many tributaries such as Susita, Jales, Bistrita, Tismana which form karst keys.

From Rovinari  to Craiova the Jiu river receves the most important tributaries, these are: Motru, Gilort and Amaradia. From Craiova down the mouth the Jiu river receves few afluents.
The most important towns situated along the Jiu river, from source to mouth are Petrosani, Lupeni, Bumbesti-Jiu, Targul-Jiu, Filiasi and Craiova.

Water from the Jiu river is used the Petrosani Depression to wash the coal, and at Rogojelu, Turceni and Isalnita the water is used for the power stations. The coal extraction from Rovinari let to the construction of the Ceauru Dam, the lake formed near the dam also has a role in keeping the water level constant when floods appear.

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In the inferior part of the Jiu river, the water is used for irrigation..