Dezful (Persian: دزفول, pronounced [dɛzˈfuːl], also Romanized as Dezfūl, Dezfool, and Dīzfūl) is a city in and the capital of Dezful County, Khuzestan Province, Iran. At the 2011 census, its population was 420,000, in 105,000 families.
The city houses a bridge that dates back to 300 BC. In 2006, the city had 235,819 inhabitants.
The name Dezful has been derived from the two words dezj (fortress)+ pol (bridge), which in combination could stand for 'the bridge to the fortress' or 'fortified bridge'. The original name of the city was Dezjpol, but after the Islamic invasion of Persia, the city was renamed Dezful. The bridge was built during the reign of Shapur I who used Roman prisoners of war to build the bridge.
The bridge protected the city from military interventions, whence the name. The old part of the city adjacent to the bridge is known as the Qaleh (castle). In the middle of the river, close to the bridge, you can see remains of several water mills built ca. 300 BC. Most of them were actually used up to the beginning of the 20th century. The last one was in use up to 1985.
The Academy of Gundishapur, a teaching hospital that was the intellectual center of the Sassanid empire, was founded near Dezful.
The people of Dezful, known as Dezfuli, Dezfoolians or Dezfulians, speak Dezfuli - a dialect distinct to Dezful and Shushtar and sometimes considered the most archaic of Persian dialects.