It is not an easy question! The longest river in the European part of Russia is the Volga. It is also the longest river in Europe. It is 3,531 kilometres long! But in the Asian part of Russia, in Siberia, there is the Lena River . It is 4,400 kilometres long! Another Siberian river- the Ob together with Irtish is even longer. It is 5,410 kilometres long.
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