The Amu Darya, the Oxus of the Greeks and Romans and the Jayhun of the medieval Arab geographers, is the great river of Central Asia’s southern edge, some 2,400 to 2,500 km long. Its headwaters rise in the Pamirs: the Pamir and Wakhan rivers join to form the Panj, and the Panj and the Vakhsh unite to form the Amu Darya proper.
In its upper course the river and its headwaters form much of Afghanistan’s northern border with Tajikistan, Uzbekistan and Turkmenistan. From there it flows north-west towards the Aral Sea, which today it no longer reaches, because so much of its water is drawn off for irrigation.
In ancient times the river was seen as the boundary between Iran and Turan, and the lands beyond it were called Transoxiana. On its Afghan bank, where the Kokcha joins it, stood Ai Khanum, a Hellenistic city with a theatre, a gymnasium and colonnaded courtyards. In Dari and Pashto the river is simply called Amu.