Dnieper River, a river in eastern Europe. It is 1,420 miles (2,285 km) long, the third longest in Europe. The Dnieper's source is in the Valdai Hills of Russia, about 140 miles (225 km) west of Moscow. From there the river flows southward through Belarus and Ukraine to the Black Sea south of Kherson. The river's name in Russian is Dnepr; in Belarusian, Dynapro; and in Ukrainian, Dnipro.

Major cities along the Dnieper include Smolensk, in Russia; Mogilev, in Belarus; and Kiev, Dnepropetrovsk, Zaporozhye, and Kherson, in Ukraine. The Dnieper is frozen over from three to four months of the year. Flooding occurs occasionally, especially during the spring thaw. Chief tributaries are the Berezina, Pripyat, Sozh, and Desna rivers.

In Ukraine the Dnieper flows through a highly productive agricultural region known especially for wheat and other grains. Large industrial complexes, particularly at Kiev, Dnepropetrovsk, and Zaporozhye, also lie along the river. Much of the industrial development along the river has been due to the presence of iron ore in the nearby Krivoy Rog basin and of coal in the nearby Donets Basin. Also important has been the availability of river transportation and abundant hydroelectric power.

Virtually the entire length of the river is navigable. Canals and canalized rivers connect the Dnieper with Poland and the Baltic Sea, and with other parts of eastern Europe.