Situated in the eastern part of the Zayandehrud River and in the vicinity of the old Saroyeh Castle and Jey Fence, the historical Shahrestan Bridge is the oldest surviving one in Isfahan with wonderful architectural style, dating back to the Sassanid era (224-651 AD).
Flanked by grove, gardens, and summer resorts, the bridge is 107 meters long with two levels of arches, 13 big sluices in the bottom and 8 small ones on the top, preventing floods as they quickened the passage of water and thus take pressure away from the structure.
Built on the natural stone floor with brick circular columns, the bridge includes two parabolic shapes, the vertical one making the middle of the bridge the highest part and the horizontal one providing a bend to the west which makes it strong enough to withstand the flow of the river.
Named Shahrestan after a village in the same name in the surrounding area, the bridge has been referred in tourists’ memoirs as the sole example of ancient military bridges, giving evidence that it had military functions.
Attached to this masterpiece of pre-Islamic architecture, there exists a building in the north side called Gomrok Khaneh (Customs House) made of adobe and brick with two small arched rooms which is believed to be the gate of entrance to Shahrestan village and was used as a tollhouse.
Nowadays in order to stop further damage, the Zayandehrud River has been diverted toward the south and an artificial lake has been built around the bridge, providing relaxing moments for visitors to enjoy the ancient site and its nice scenic environs.