The Jiul de Est ("Eastern Jiu", previously also known as Jiul Unguresc) is a headwater of the river Jiu in Romania. Its source is in the Șureanu Mountains. At its confluence with the Jiul de Vest in Iscroni, the Jiu is formed. Its length is 29 km (18 mi) and its basin size is 468 km2 (181 sq mi). Jiul means "the Jiu" (with the definite article -l).