The Seret River (Ukrainian: Серет) is the left tributary of the Dniester that flows through the Ternopil Oblast of Ukraine. Its length is 242 km; the basin covers some 3900 km2. The towns of Ternopil, Terebovlia and Chortkiv sit along the river's banks. Some of the bloodiest fighting of the Great War took place on the banks of the Seret.