The princely state of Dungarpur was situated in the south of Rajputana with an area of 1,447 square miles. Earlier the territories of Dungarpur and Banswara comprised of a place called Bagar, a land of ‘five gems, namely water, rocks, leaves, abusive language, and the looting of clothes', as a couplet says. It was occupied mostly by Bhils and to a smaller extent by Chauhan and Paramara Rajputs. Towards the end of the twelfth century, Karan Singh was chief of Mewar whose country was being ravaged by Rang Mokal, a Parihar Rajput of Mandor in Jodhpur. He first sent his eldest son Mahup against the invader but on his failing, sent his second son, Rahup who brought the Parihar back a prisoner and was thereupon declared heir apparent. Displeased at this, Mahup left his father and after staying for a few years at AHAR (near Udaipur) proceeded south. He took up his abode with his mother's people, the Chauhans of Bagar. Here he gradually drove back the Bhil chieftains and became master of that area.
The chiefs of Dungarpur descended from Mahup, and consequently claimed that they belonged to an elder branch of the family which ruled Mewar. However there is no concrete evidence to prove this allegation.
From the fact of Mahup having resided for some time at Ahar, the Dungarpur family was called Ahariyas. Rawal Deda said to have been sixth in descent from Mahup, seized the town of Galiakot in the south-east from the Paramaras and made it his residence. Later on Rawal Bir Singh founded Dungarpur Town naming it after a Bhil chieftain Dungaria, whom he assassinated.