Claim: The Caspian Sea is bounded by the Republic of Azerbaijan to the west.

The Caspian Sea is the largest enclosed inland body of water on Earth by area , variously classed as the world 's largest lake or a full-fledged sea . It is in an endorheic basin -LRB- a basin without outflows -RRB- located between Europe and Asia . It is bounded by Kazakhstan to the northeast , Russia to the northwest , Azerbaijan to the west , Iran to the south , and Turkmenistan to the southeast .   The Caspian Sea presently lies about 28 m below sea level in the Caspian Depression , to the east of the Caucasus Mountains and to the west of the vast steppe of Central Asia . The sea bed in the southern part reaches as low as 1023 m below sea level , which is the second lowest natural depression on earth after Lake Baikal -LRB- -1180 m -RRB- . The ancient inhabitants of its coast perceived the Caspian Sea as an ocean , probably because of its saltiness and large size .   The sea has a surface area of 371000 km2 -LRB- not including the detached lagoon of Garabogazköl -RRB- and a volume of 78200 km3 . It has a salinity of approximately 1.2 % -LRB- 12 g/l -RRB- , about a third of the salinity of most seawater .