a river of European Russia, rises in the government of Orel, and flows N.E. through those of Tula, Kaluga, Moscow, Riazan, Vladimir, and Nijni-Novgorod. After a course of about 600 miles, it falls into the Volga at the town of Nijni-Novgorod. It is navigable as far as Orel, and is of great commercial importance, affording an easy means of communication for the produce of the different regions on its banks. The country that it waters is the most fertile portion of the Russian empire, and has an area of 127,000 square miles. It receives numerous tributaries; of which the most important are the Upsa, Jizdra, Nara, Moskva, Tzna, and Kliasma.