The township of Dezful lies at a distance of 721 km. from Tehran, and is located to the north of Khuzestan province. Generally, it has a desert like and comparatively dry weather with hot summers and moderate winters. The word Dezful has been derived from the words 'Dejpol' or 'Despool', and in local language it is known as 'Dezpeel'. It is said that the people who constructed the bridge, erected a fort or "Dej" right at the beginning of the same to protect the bridge. Since then the name of "Dejpol" (fort bridge) has remained on this city.
Alike the city of Shooshtar, Dezful surpassed the city of Jondishahpur. On destruction of the latter, Dezful progressed to a greater extent. later on due to the devastating state of its water network, which was from the Sassanide period, the city and its surroundings were subject to heavy damages.
Although, Dezful remained safe from the Mongol attacks, but later on came under the Ilkhanan jurisdiction, and did not show any resistance against the attacks of Amir Teimoor. Nader Shah was responsible for safeguarding this vicinity against the Lors, and thereby erected a castle called Dej Shah a few kilometers to the northeast of Behbahan. Presently Dezful is one of the thriving and important cities of Khuzestan province.