Gavmishan Bridge پل گاومیشان
The bridge in modern day
Coordinates	33°05′02″N 47°32′15″E / 33.08389°N 47.53750°E / 33.08389; 47.53750
Crossed	Seymareh River
Locale	Border of Ilam and Lorestan Provinces
Maintained by	ICHTO
Heritage status	Iran National Heritage List
Registry Number	2222
Characteristics
Design	Arch
Material	Mortar, Brick and Rock
Total length	175 m (574 ft)
Width	8.2 m (27 ft)
Traversable?	No
Longest span	33.7 m (111 ft)
No. of spans	6
Piers in water	2
Design life	Around 1400 years
History
Construction end	Late Sasanian Era
Collapsed	During Muslim Conquest of Persia
Location

Gavmishan Bridge is a historic bridge in Darreh Shahr County, Ilam Province, Iran. The bridge was built in the late Sasanian era on Karkheh River, parts of which constitute the modern-day border of Ilam and Lorestan provinces.^[1][2] It is 175 m (574 ft) in length and about 8 m (26 ft) in width. It has the longest arch span among the ancient bridges in Iran and the world. Many experts consider it an engineering feat, considering the time when it was built, the material used and the floods it has withstood during its age of 1,400 years.^[3][4]

It is believed that the bridge was intentionally destroyed by the Persian army to stop or slow down the invasion of Arabs during the Muslim Conquest of Persia in the 7th century.^[5]

The bridge passes Karkheh river, which is the confluence of Seymareh and Kashkan rivers. Nowadays, Seymareh and Karkheh indicate the eastern border of Ilam Province.

It is 20 km east of Darreh Shahr, and 30 km from Pol-e Dokhtar, near the modern bridge.

According to texts, the bridge was once restored by Vaali of Posht-Kooh about 200 years ago.^[1]

Being on the border of Ilam and Lorestan provinces has resulted in many disputes regarding ownership of the bridge. Nevertheless, the latest restoration took place between 2005 and 2008 with funding from Ilam province.