Khwarazm or Chorasmia is a large oasis region on the Amu Darya river delta in western Central Asia, bordered on the north by the (former) Aral Sea, on the east by the Kyzylkum Desert, on the south by the Karakum Desert, and on the west by the Ustyurt Plateau. It was the center of the Iranian Khwarezmian civilization, and a series of kingdoms such as the Afrighid dynasty and the Anushtegin dynasty, whose capitals were Kath, Gurganj and—from the 16th century on—Khiva. Today Khwarazm belongs partly to Uzbekistan and partly to Turkmenistan.

The Amu Darya, also called the Amu, the Amo, and historically the Oxus, is a major river in Central Asia, which flows through Tajikistan, Turkmenistan, Uzbekistan and Afghanistan. Rising in the Pamir Mountains, north of the Hindu Kush, the Amu Darya is formed by the confluence of the Vakhsh and Panj rivers, in the Tigrovaya Balka Nature Reserve on the border between Afghanistan and Tajikistan, and flows from there north-westwards into the southern remnants of the Aral Sea. In its upper course, the river forms part of Afghanistan's northern border with Tajikistan, Uzbekistan, and Turkmenistan. In ancient history, the river was regarded as the boundary of Greater Iran with Turan, which roughly corresponded to present-day Central Asia. The Amu Darya has a flow of about 70 cubic kilometres per year on average.