river in Russia, tributary of Volga
The Oka (Russian: Ока́, IPA: [ɐˈka]) is a river in Russia. It is a tributary of the Volga River. The Moskva River, which is the main river in Moscow, flows into it. The river is very long and is 1,500 km (930 mi) long.
|Cities||Oryol, Kaluga, Serpukhov, Kolomna, Ryazan, Murom, Dzerzhinsk, Nizhny Novgorod|
|- location||Oryol Oblast|
|- elevation||226 m (741 ft)|
|- location||Nizhny Novgorod|
|- elevation||67 m (220 ft)|
|Length||1,500 km (930 mi)|
|Basin size||245,000 km2 (95,000 sq mi)|
|- average||1,260 m3/s (44,000 cu ft/s)|
- "Река Ока". Russian State Water Registry (in Russian).