Inland salt lake between Europe and Asia, bordering Azerbaijan, Russia, Kazakhstan, Turkmenistan,and Iran.
With a basin 750 mi (1,200 km) long and 270 mi (434 km) wide and an area of 143,550 sq mi (371,795 sq km), it is the largest inland body of water in the world.
The Caucasus Mts. rise from the south-western shore, and the Elburz Mts. parallel the southern coast. The Caspian receives the Volga (which supplies more than 75% of its inflow), Ural, Emba, Kura, and Terek rivers, but has no outlet.
The chief ports on the Caspian are Baku, a major oil centre, and Astrakhan, at the mouth of the Volga.
It was important as a commercial route in the premodern era, when it formed part of the Mongol-Baltic trade route for goods from Asia.
Underlying the Caspian are some of the world's largest oil reserves, and the five surrounding countries, all with major stakes in oil-field development, have disputed zones of control. The Caspian also has important fisheries.
The northern part of the sea is the chief source of beluga caviar, but the destruction of spawning areas and illegal fishing has greatly reduced the number of sturgeon, and fishing quotas have been imposed.