Ancient Mesopotamia encompasses all of the country of Iraq. Some parts of Turkey, Syria and Iran area also overlap with the old borders of Mesopotamia.
Mesopotamia is also called the Fertile Crescent and encompasses the area between and around two important rivers: the Tigris and the Euphrates. Another name for this area is the cradle of civilization, due to the multiple ancient civilizations that rose in the area, such as the Sumerians and the Akkadian Empire. The two rivers provided enough water and fertilized land to support settlements, so the hunter-gatherer lifestyle was no longer necessary. On this land, settlers were able to begin farming and domesticating animals, which led to complex civilizations.