Moskva River. The Moskva is a river that flows through Western Russia. It rises about 140 kilometers (87??mi) west of Moscow and flows roughly east through the Smolensk and Moscow Oblasts, passing through central Moscow. About 110 kilometers (68??mi) southeast of Moscow, at the city of Kolomna, it flows into the Oka, itself a tributary of the Volga, which ultimately flows into the Caspian Sea.