Surrounded by four countries (Iran, Iraq, Türkiye and Syria), the Tigris River is the second largest river in western Asia. With the Euphrates River, it makes up a river system that borders Mesopotamia in the area known as the Fertile Crescent. An important source of both travel and irrigation, the Tigris also has a rich history that dates back to the earliest known civilizations because of its importance to a largely arid region.

Originating in Lake Hazer in Türkiye—a region characterized by high mountains—the river flows parallel with the Euphrates River. The two eventually join, emptying into the Persian Gulf in the lowlands in an area known as the Shatt Al-Arab. More than half of the Tigris can be found in Iraq. Other rivers that flow into it include the Greater Zab, the Lesser Zab, the Al-Adhaim, the Diyala and the Karkheh.

While the local population uses the Tigris as a source of fresh water, agriculture is the primary focus for the people near the river. The region’s low rainfall and hot, dry summers mean that irrigation is necessary for growing crops. While such irrigation can sometimes lead to problems in water quality, the Tigris is generally considered to have acceptable quality.

The Tigris is also used for hydropower, which has led to the construction of dams in the region to harness the power of its flow. The work of Julia Harte, under funding from a National Geographic grant, explored the consequences of using such power on the history and people of the area. Innovations and advancements along the same lines of hydropower will continue to create an evolving landscape for local governments and people of the region.