Shushtar is a city in the capital of Shushtar County, Khuzestan Province, Iran.
Shushtar is located approximately 92 kilometers away from Ahwaz. Much of its past agricultural productivity derives from Roman-built irrigation system which centered on the band-e Kaiser the first dam bridge in Iran. The modern name Shushtar is connected with the name of another ancient city called Susa which means greater than Shush. During Sassanian era, it was an island city on the Karun River and selected to become the summer capital.
Shushtar can be traced back to Darius the Great in the 5th century B.C. and it involved the creation of two main diversion canals on the river Karun one of which, Gargar canal, is still in use providing water to the city of Shushtar via a series of tunnels that supply water to mills.