Surrounded by four countries (Iran, Iraq, Turkey, and Syria), the Tigris River is the second largest river in western Asia. With the Euphrates, it makes up a river system that borders Mesopotamia in the area known as the Fertile CrescentFertile CrescentThe Fertile Crescent is a large geographic region in modern day Turkey, Iran, Iraq, Syria, Israel, Jordan, and the northern-easternmost part of Egypt, fed by the Euphrates and Tigris rivers, which have supported numerous ancient civilizations.
› heritage-fertile-crescentHeritage of the Fertile Crescent | National Geographic Society.Apr 26, 2019