The Volga (Во́лга) is the longest river in Europe. Situated in Russia, it flows through Central Russia to Southern Russia and into the Caspian Sea. The Volga has a length of , and a catchment area of . It is also Europe's largest river in terms of average discharge at delta – between and – and of drainage basin. It is widely regarded as the national river of Russia. The hypothetical old Russian state, the Rus' Khaganate, arose along the Volga 830 AD. Historically, the river served as an important meeting place of various Eurasian civilizations.
The river flows in Russia through forests, forest steppes and steppes. Five of the ten largest cities of Russia, including the nation's capital, Moscow, are located in the Volga's drainage basin.
Some of the largest reservoirs in the world are located along the Volga River. The river has a symbolic meaning in Russian culture – Russian literature and folklore often refer to it as Волга-матушка Volga-Matushka (Mother Volga).
The Russian hydronym () derives from Proto-Slavic *vòlga 'wetness, moisture', which is preserved in many Slavic languages, (влага) 'moisture', Bulgarian () 'moisture', Czech 'dampness', Serbo-Croatian: vlaga () 'moisture', Slovene 'moisture', Polish wilgoć 'moisture' and Macedonian () 'moisture', among others.
The Scythian name for the Volga was , literally meaning 'wetness'. This is related to the Avestan name for a mythical stream, (), which means "wet" or "moisture," and was derived from Proto-Indo-European or ).
This name can be compared several Indo-Iranic terms, such as:
Sogdian () 'vein, blood vessel' (from Old Iranian ),
Persian رگ 'vein,'
Vedic Sanskrit () 'dew, liquid, juice; mythical river'), which was also the name of a tributary of the Indus river.
The Scythian name survives in modern Moksha as ().
The Greek author Herodotus recorded two more ancient Iranic names of the Volga:
(Οαρος; Oarus), which was derived from Scythian , meaning "broad."
The Huns' name of the Dnipro river, Var, was also derived from Scythian .