Kura (Caspian Sea) emptying into the Caspian Sea at Neftçala. Most of the Kura River runs in the broad and deep valley between the Greater Caucasus and Lesser Caucasus mountains, and the major tributary, the Aras, drains most of the southern Caucasus and the mountain ranges of the extreme northern Middle East. The entirety of Armenia and most of Azerbaijan are drained by the Kura River, but the Kura does not pass through Armenia at all. Also in the Kura watershed are Turkey, Georgia, and a bit of northern Iran. Most of the elevation change in the river occurs within the first .
Caspian Sea is the saline eastern inlet of the Caspian, which is part of Turkmenistan and at times has been a lake in its own right due to the isthmus that cuts it off from the Caspian. Differences between the three regions are dramatic. The Northern Caspian only includes the Caspian shelf, and is very shallow; it accounts for less than 1% of the total water volume with an average depth of only . The sea noticeably drops off towards the Middle Caspian, where the average depth is . The Southern Caspian is the deepest, with oceanic depths of over , greatly