Located 25 km southwest of Foman city north of Iran in Gilan province, it is a military complex which had been constructed during the Seljuk Dynasty by followers of the Ismā'īlī sect. The castle is built on two tips of a mount, with an area of . Its architects have benefited from natural mountainous features in the construction of the fort. The Rudkhan Castle River originates in the surrounding heights and flows from south to north. After crossing a mountainous winding route with dense forests, the first thing that one notices about the castle is its big entrance gate.