Aras

The Aras River is a Caucasus river. It begins in eastern Turkey and travels along the boundaries of Turkey and Armenia, Turkey and the Azerbaijani exclave of Nakhchivan, Iran and both Azerbaijan and Armenia, and eventually through Azerbaijan to the Kura River. It drains the south side of the Lesser Caucasus Mountains, whereas the Kura drains the north side. The river's overall length is 1,072 kilometers (666 miles), and its watershed area is 102,000 square kilometers (39,000 square miles). The Aras is the fifth-longest river in Turkey.

The Aras became significant as a geographic political barrier in modern history. The river was designated as the border between the Russian Empire and Qajar Iran under the conditions of the Treaty of Gulistan and the Treaty of Turkmenchay, as the latter was obliged to yield its Caucasian lands to Russia. Because of these 19th-century border revisions, one current, but not widely recognized, the system designates the Aras River as the continental dividing line between Europe and Asia.

Length: 666 miles (shared with Armenia, Azerbaijan, and Iran)