Oka (river)

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Oka
The Oka riverbank in Nizhny Novgorod
Map of the Volga watershed with the Oka highlighted
Native name	Ока́ (Russian)
Location
Country	Russia
Cities	Oryol, Kaluga, Serpukhov, Kolomna, Ryazan, Murom, Dzerzhinsk, Nizhny Novgorod
Physical characteristics
Source
• location	Oryol Oblast
• coordinates	52°21′45″N 36°13′20″E / 52.36250°N 36.22222°E / 52.36250; 36.22222
• elevation	226 m (741 ft)
Mouth	Volga
• location	Nizhny Novgorod
• coordinates	56°19′55″N 43°58′53″E / 56.33194°N 43.98139°E / 56.33194; 43.98139
• elevation	67 m (220 ft)
Length	1,500 km (930 mi)
Basin size	245,000 km2 (95,000 sq mi) 244,308.3 km2 (94,328.0 sq mi)[1]
Discharge
• location	Nizhny Novgorod (near mouth)
• average	1,260 m3/s (44,000 cu ft/s) 1,327.15 m3/s (46,868 cu ft/s)[2]
Discharge
• location	Ryazan (Basin size: 97,995.8 km2 (37,836.4 sq mi)
• average	585.477 m3/s (20,675.9 cu ft/s)[3]
Discharge
• location	Kaluga (Basin size: 54,877.8 km2 (21,188.4 sq mi)
• average	305.042 m3/s (10,772.5 cu ft/s)[4]
Basin features
Progression	Volga→ Caspian Sea
Tributaries
• left	Moskva, Klyazma
• right	Moksha

The Oka (Russian: Ока́, IPA: [ɐˈka]) is a river in central Russia, the largest right tributary of the Volga. It flows through the regions of Oryol, Tula, Kaluga, Moscow, Ryazan, Vladimir and Nizhny Novgorod and is navigable over a large part of its total length, as far upstream as the town of Kaluga. Its length is 1,500 km (930 mi) and its catchment area 245,000 km² (95,000 sq mi).^[5] The Russian capital Moscow sits on one of the Oka's tributaries—the Moskva.