It flows southward through the Romanian counties Hunedoara, Gorj, Mehedinți and Dolj before flowing into the Danube near Zăval,[3] a few kilometers upstream from the Bulgarian city of Oryahovo. It is 339 kilometres (211 mi) long, including its source river, Jiul de Vest.[2][4] It has a basin of 10,430 km2 (4,030 sq mi).[2][4][5] Its average discharge at the mouth is 97 m3/s (3,400 cu ft/s).[4]
The upper Jiu Valley, around Petroșani and Lupeni, is Romania's principal coal mining region.
^"Planul național de management. Sinteza planurilor de management la nivel de bazine/spații hidrografice, anexa 7.1" (PDF, 5.1 MB). Administrația Națională Apele Române. 2010. p. 538.
^ a b c dAtlasul cadastrului apelor din România. Partea 1 (in Romanian). Bucharest: Ministerul Mediului. 1992. pp. 239–255. OCLC 895459847. River code: VII.1
^Jiu (jud. Dolj), e-calauza.ro
^ a b c"Danube River Basin District, Part A - Roof Report" (PDF). ICPDR. April 2004. p. 12.