Tigris

Tigris is the easternmost of Mesopotamia's two river systems, the Euphrates is the other. The river travels south from the Armenian Highlands mountains, via Syria and the Arabian Deserts, and into the Persian Gulf.

The Tigris is 1,750 kilometers long, rising in the Taurus Mountains of eastern Turkey around 25 kilometers southeast of Elazig and 30 kilometers from the Euphrates' headwaters. The river then flows through Southeastern Turkey for 400 kilometers until joining the Syria-Turkey border. The only segment of the river that runs through Syria is this 44-kilometer stretch. Garzan, Anbarçayi, Batman, and the Great and Little Zab are among its affluence.

The Tigris divides into multiple channels at its confluence with the Euphrates. The artificial Shatt al-Hayy is the first to split off, joining the Euphrates near Nasiriyah. Second, the Central Marshes are fed by the Shatt al-Muminah and Majar al-Kabir. Two further distributary waterways branch off further downstream to supply the Hawizeh Marshes. The Al-Kassarah, which drains the Hawizeh Marshes, joins the main river as it proceeds south. Finally, near al-Qurnah, the Tigris joins the Euphrates to form the Shatt-al-Arab. Pliny and other ancient historians claim that the Euphrates once had a separate outlet into the sea from the Tigris.