Upper Mesopotamia is the name used for 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 (Arabic: الجزيرة "the island", also transliterated Djazirah, Djezirah, Jazirah) 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 region extends south from the mountains of Anatolia, east from the hills on the left bank of the Euphrates river, west from the mountains on the right bank of the Tigris river and includes the Sinjar plain. It extends down the Tigris to Samarra and down the Euphrates to Hīt. The Khabur runs for over 400 km (250 mi) across the plain, from Turkey in the north, feeding into the Euphrates.
The major settlements are Mosul, Deir ez-Zor, Raqqa, al-Hasakah, Diyarbakır and Qamishli. The western, Syrian part, is essentially contiguous with the Syrian al-Hasakah Governorate and is described as "Syria's breadbasket". The eastern, Iraqi part, includes and extends slightly beyond the Iraqi Nineveh Governorate. In the north it includes the Turkish provinces of Şanlıurfa, Mardin, and parts of Diyarbakır Province.