Forest areas intermingle with large river valleys and numerous lakes varying greatly in size. Belarus has 20,800 rivers and streams, only 3,000 of which are more than 5 kilometers in length. They flow between the Baltic and Black Sea basins. Rivers that begin in one location but flow separately through different basins have been united by canals. The Dnieper, Pripyat, Berezina, Sozh, Zapadnaya Dvina, Nieman and Viliya are the biggest rivers, with more than 500 kilometers in length.
Rivers are more frequent in the North than in the South.
More than 11,000 lakes cover an area of almost 2,000 square kilometers. The highest concentration of lakes is in the North West of the Republic, and the lowest in its central part. Containing more than 2,000 blue lakes, saucer-like in appearance, the North has come to be known as the lake belt. Most of these lakes, formed in the hollow of small basins, have very steep banks that suddenly reach out into flat plateau. Its length stretches almost 13 km from West to East.