The Caspian Sea is bordered on the northwest by Russia, on the northeast by Kazakhstan, on the west by Azerbaijan, on the southeast by Turkmenistan, and on the south by Iran. It is classified as both a sea and a lake, and it is the largest enclosed inland body of water in the world.
The Ancient Romans named the Caspian Sea after the Caspi tribe that lived in the area. At its deepest point, the Caspian Sea is over 3,000 feet deep. The Caspian Sea has approximately a third of the saltiness of seawater. This saltiness caused ancient inhabitants to think it was an ocean. There are many islands near the coasts of the Caspian. It has no outlet; instead most of the water evaporates in the Kara-Bogaz-Gol, a shallow bay north of the Caspian.
The Caspian is divided into the Northern, Middle, and Southern Caspian. The Mangyshlak Threshold divides the Northern and Middle regions, while the Apsheron Threshold divides the middle and southern regions. The southern region is the largest and deepest, accounting for about 66 percent of the volume of the Caspian Sea. The middle region makes up about 33 percent of the Caspian, while the northern region is less than 1 percent.