The Aras (also known as Araks, Arax, Araxi, Araxes, Araz, or Yeraskh; Արաքս, ارس, Aras, Araz, Aras or Araz; Аракс) is a river located in and along the countries of Turkey, Armenia, Iran, and Azerbaijan. Its total length is 1,072 kilometers (665 miles). Given its length and a basin that covers an area of 102,000 km², it is one of the largest rivers of the Caucasus.
The Aras River rises near Erzurum, Turkey. It meets with the Akhurian River southeast of Digor, flows along the Turkish-Armenian border, and then near a corridor that connects Turkey to Azerbaijan's Nakhichevan exclave. It then flows along the Iranian-Nakhichevan and the Iranian-Armenian border. The river then flows along the border between Iran and the main territory of Azerbaijan and then turns into Azerbaijan to meet with the Kura River at the village of Sabirabad. It then directly flows into the Caspian Sea. About 101,937 km² of the Araz River basin is located in Azerbaijan.
The Zangmar, Sariso, Ghotour River, Hajilar River, Kalibar River, Ilghena River, Darreh River and Balha River are the major tributaries of the Aras from the south (right). In Turkey the Ghareso river flows in on the left side. The Akhurian, Metsamor, Hrazdan, Azat, Vedi, Arpa, Vorotan, Voghdji and Megri rivers flow in from the Armenian north side (left). The Khachin River, Okhchi River, Kuri River and Kandlan River flow in from the Azerbaijan north side (left).
In Armenian tradition, the river is named after Arast, a great-grandson of the legendary Armenian patriarch Haik. The name was later Hellenized to Araxes and was applied to the Kura-Araxes culture, a prehistoric people which flourished in the valleys of the Kura and Aras. But many times it is the Volga River which is called Araxes especially in Herodotus' History first chapter - The First of Book the Histories, Called Clio. The river is also mentioned in the last chapter of the Aeneid VIII by Virgil, as "angry at the bridge", since the Romans built a bridge over it,so that it is thereby conquered. By some, the river Aras has been associated with the otherwise unidentified Gihon and Pishon rivers mentioned in the second chapter of the Bible.
In modern history, the Aras gained significance as a geographic political boundary. Under the terms of the Treaty of Gulistan and the Treaty of Turkmenchay, the river was chosen as the border limit between the Russian and Persian Empires. Iran and the Soviet Union later built a joint dam on the Aras at Poldasht area.