The Dnieper, also called Dnepr or Dnipro, is one of the major transboundary rivers of Europe, rising in the Valdai Hills near Smolensk, Russia, before flowing through Belarus and Ukraine to the Black Sea. Approximately 2,200 km long, with a drainage basin of 504,000 square kilometres, it is the longest river of Ukraine and Belarus and the fourt…The Dnieper, also called Dnepr or Dnipro, is one of the major transboundary rivers of Europe, rising in the Valdai Hills near Smolensk, Russia, before flowing through Belarus and Ukraine to the Black Sea. Approximately 2,200 km long, with a drainage basin of 504,000 square kilometres, it is the longest river of Ukraine and Belarus and the fourth-longest river in Europe, after the Volga, Danube, and Ural rivers.