Dnieper or Dnepr, river and important traffic artery of Ukraine, Belarus, and Russia, 2,290 km (1,420 mi) long. The Dnieper is the third longest river of Europe, exceeded in length only by the Volga and Danube rivers. The Dnieper rises southwest of Moscow, in the Valday Hills, and flows in a general southerly direction to empty into the Black Sea, near Kherson, in Ukraine. The Dnieper is navigable throughout its entire course and is entirely ice-free for eight months of the year.

The Dnieper drains an area of about 518,000 sq km (about 200,000 sq mi). The upper course of the river flows partly through hilly country and skirts the eastern end of the Poles’ye (Pripet Marshes). The middle and lower reaches pass through the fertile agricultural and highly industrialized areas of Ukraine, where the river attains its greatest breadth: about 2 km (about 1 mi). The chief tributaries of the Dnieper are the Berezina, Desna, and Pripyat’ rivers. Kyiv is the principal city on the Dnieper. Other important cities on the river include, from south to north, Kherson, Zaporizhzhya, Dnipropetrovs’k, and Dniprodzerzhyns’k in Ukraine, Mahilyow in Belarus, and Smolensk in Russia. A large hydroelectric power station above Zaporizhzhya supplies power to the cities along the southern reaches of the river. Grain, lumber, and metals are transported on the Dnieper.

In ancient times the Dnieper was an important commercial artery between the northern and southern parts of Eastern Europe. As the size of ships increased, the commercial importance of the Dnieper lessened, principally because of the impossibility of navigating the rapids above Zaporizhzhya. The problem of making the entire river navigable was solved in 1932, when the great Dniprohes Dam and hydroelectric station above Zaporizhzhya was completed. The dam sufficiently raised the water level above the rapids to allow vessels to pass safely. Construction of canals linking the Dnieper with the Bug River, and the Berezina and Pripyat’ rivers with the Daugava (Western Severnaya Dvina) and Neman (also Nyoman or Nemunas) , respectively, made the Dnieper the main link in a waterway from the Black to the Baltic seas.