Shushtar is a large town in the province of Khuzistan, Iran. Geographically, Shushtar lies at the eastern edge of Susiana, the flat, fertile region around ancient city of Susa, which was the heart of the Elamite Empire. Susiana itself is the easternmost part of Mesopotamia, and is geographically and culturally connected to lower Iraq. The town lies along the Karun River, one of Iran's most important waterways, just as it takes a sharp turn west before turning southwest again. Along this stretch of the river, numerous canals dug in antiquity divert waters from the Karun to irrigate the fields on the surrounding plain, which were famous for the production of rice, sugarcane, and orchards. The old city is actually on an island formed by two of these canals: the Ab-i Gargar, which runs through a gorge to the east of the town, and the Ab-i Minaw, which runs to the west closer to the Karun and forks into several secondary canals. Remnants of ancient hydraulic works dot the landscape in and around the town, as this was an important economic region for the Sasanian and Parthian empires. Most famously, Shushtar is home to the ruins of the bridge-dam known as Band-i Qaysar or Pul'band-i Shadurvan, constructed under Sasanian Emperor Shapur I, and a complex of watermills powered by rapids and diverted water from the Ab-i Gargar.

Popular legend attributes its foundation to the mythical ancient Persian king Hushang who declared the site "more pleasant" (shush-tar) than Susa to the northwest, giving the site its name.1 Toponyms similar to Shushtar appear in Roman and Syriac texts, suggesting that the site has been populated since classical antiquity. During the Sasanian period, the region saw the developments described above and may have also experienced an increase in urban populations.² During this time, the city became the seat of a Nestorian Bishopric and was home to many Christians, perhaps including in their number the descendants of the Roman soldiers captured at Edessa who are said to have constructed Shushtar's bridge-dam. This image of Shushtar as religiously mixed fits with that of greater Sasanian Mesopotamia, which was home to Jewish, Christian, and Zoroastrian communities.

The city entered Islamic rule circa 638/17 AH, and remained an important provincial center, famous for its silks and produce, although eclipsed in terms of size by the city of Ahwaz to the south and in prestige by Gundishapur to the northeast. In the tenth/fourth century AH, the Jerusalemite geographer al-Muqaddasi described the area as pleasant and abundant in produce, although he does not describe the city of Shushtar itself.3 Unlike central Mesopotamia, Khuzistan did not suffer greatly from the Mongol invasion and accession of Iran and Iraq during the thirteenth/seventh century AH and in fact attained greater importance with the decline of Gundishapur.4 

Shushtar continued on as a relatively prosperous provincial center until the nineteenth century, when a series of outbreaks of diseases ravaged the population and two floods on the Karun resulted in the rupture of the Band-i Qaysar, leading to a decline in cultivable lands south of the city. 

Notes:

1. Lockhart, Persian Cities, 142.
2. Adams, "Agriculture and Urban Life," 119.
3. Muqaddasi, Ahsan al-Taqasim, 358 and 361-362.
4. Lockhart, Persian Cities, 147-148.