Oka (Russian: Ока́) is a large river in Russia, the largest right tributary of the Volga. It flows through the Oblasts of Oryol, Tula, Kaluga, Moscow, Ryazan, Vladimir and Nizhny Novgorod. Its length exceeds 1500 km (932 miles).

The name of Oka is cognate to aqua, the Latin word for "water" , and to the name of the Aa Rivers. Historically, the river gave its name to the Upper Oka Principalities, situated upstream from Tarusa. One of the largest Russian cities, Nizhny Novgorod, was founded to protect the Oka's confluence with the Volga. The Russian capital, Moscow, sits on one of the Oka's tributaries - the Moskva River.

Cities and towns on Oka

• Orel
• Kaluga
• Serpukhov
• Pushchino
• Kolomna
• Ryazan
• Murom
• Dzerzhinsk
• Nizhny Novgorod

Rivers of Russia

Ока (река) | Oka (Fluss, Wolga) | Oka | Okao | Oka (rivière) | 오카 강 | Oka | Occa | Oka (Europa) | Ока (река) | Ока (река) | Oka | Oka