The Protva () is a river in the

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

and

Kaluga Kaluga (, ) is a types of inhabited localities in Russia, city and the administrative center of Kaluga Oblast, Russia. It stands on the Oka River southwest of Moscow. Its population was 337,058 at the 2021 census. Kaluga's most famous residen ...

oblasts in

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. It is a left

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the Oka. It is long, and has a drainage basin of .«Река ПРОТВА»
Russian State Water Registry The area of its basin is . The Protva freezes up in early December and stays icebound until early April. Its main tributary is the Luzha. The towns of Vereya, Borovsk, Protvino and Obninsk are located on the shores of the Protva.

References

Rivers of Kaluga Oblast Rivers of Moscow Oblast {{Russia-river-stub