Māzandarān (Persian: مازَنْدران) is an important place in Shahnameh, the national epic of Greater Iran. It should not be confused with Mazandaran Province in northern Iran, formerly known as Tabarestan. Beside Shahnameh, there are also references to Mazandaran in Avesta.
In Shahnameh, Mazandaran in the land of great Divs (demons). It is such a horrible place that no Shah of Iran dare to go there and conquer the land. One day a Div comes to Kai Kavus and reads a poem for him and describes the beauties of Mazandaran. Being impressed by the Div's description, Kai Kavus, who is an irrational and unwise man, decides to conquer Mazandaran. Everyone is opposed to this decision, because even great kings such as Jamshid and Fereydun didn't try to conquer the land, nonetheless, Kai Kavus insists on it. He goes there, but was defeated and imprisoned by the Div's of Mazandaran. He and two-thirds of his army were blinded by Divs. He wrote a letter to Zāl and asks him to come to Mazandaran and rescue him. But Zaal is old and he can't go there himself. Instead, he sends Rostam, who is a child at the moment, to Mazandaran. Rostam has to pass Haft Khan in order to get to Mazandaran.
Prior to the above story, there are some references to Mazandaran in the story of Zaal and Rudaabe. It seems that Sām, the grandfather of Rostam, had conquered Mazandaran at the time of Manuchehr.
Mazandaran is inhabited by a population that are different to Iranians. They don't believe in God, instead they are magicians and for this reason, they could not be defeated by man power, only the God's power could defeat them.
It is not clear where Mazandaran is located – various places have been suggested. Some scholars believe that Mazandaran is a region in India, others believe that Mazandaran is in Levant and Egypt. But there is no consensus between scholars.