At which river did Genghis Khan defeat Jalal ad-Din in 1221?

Genghis Khan defeated Jalal ad-Din at the Indus River in 1221.

The battle took place on 24 November 1221 during the Mongol invasion of the Khwarazmian Empire. Jalal ad-Din Mangburni, the son and successor of Shah Muhammad II, had escaped westward Mongol pursuit and rebuilt an army around Ghazni after defeating a Mongol force at Parwan.

Genghis Khan personally led the Mongol army against him. The Mongols pinned Jalal ad-Din’s forces against the river and eventually broke their position. Facing defeat, Jalal ad-Din rode his horse over a steep bank into the Indus and reached the opposite shore, an escape later celebrated in historical accounts.

The Oxus River, also called the Amu Darya, was important earlier in the Mongol invasion and marked part of the region’s geography, but it was not the site of this decisive 1221 battle. The Tigris and Syr Darya likewise belong to other stages of the wider conflict.