The Volga is the longest river of Europe, stretching over 3, 530 kilometers from its source in the Valdai Hills in central Russia to its delta in the Caspian Sea. It is the longest river in Europe and the 15th longest river in the world. The Volga is also the most voluminous river in Europe, with an average discharge of 6, 400 cubic meters per second. It is also one of the most important rivers in Russia, providing water for irrigation and hydroelectric power.