Upper Mesopotamia constitutes the uplands and great outwash plain of northwestern Iraq, northeastern Syria and southeastern Turkey, in the northern Middle East. Since the early Muslim conquests of the mid-7th century, the region has been known by the traditional Arabic name of al-Jazira and the Syriac variant Gāzartā or Gozarto (ܓܙܪܬܐ). The Euphrates and Tigris rivers transform Mesopotamia into almost an island, as they are joined together at the Shatt al-Arab in the Basra Governorate of Iraq, and their sources in eastern Turkey are in close proximity.

The Khabur River is the largest perennial tributary to the Euphrates in Syria. Although the Khabur originates in Turkey, the karstic springs around Ras al-Ayn are the river's main source of water. Several important wadis join the Khabur north of Al-Hasakah, together creating what is known as the Khabur Triangle, or Upper Khabur area. From north to south, annual rainfall in the Khabur basin decreases from over 400 mm to less than 200 mm. This has made the river a vital water source for agriculture throughout history. The Khabur joins the Euphrates near the town of Busayrah.