This was the first city of Delhi and was established by Chauhan Rajputs. King Vigraharaj defeated Tomar Rajputs and captured Delhi and Ajmer from them in the latter half of the 12th century. His grandson and successor, Pirthviraj Chauhan built the city of Rai Pithora. The city derived its name from the title of Prithviraj Chauhan and was an extention of an earlier fort by Tomar Rajputs known as Lal Kot. The Chauhans only fortified it with high-rise walls and ramparts. The ruins of Lal kot still form its western base.

The materials used for building Pithora primarily consisted of rubbles from the previously raised city. The ramparts are at least 5 to 6 meters thick at various places. It height varies from 10 meters to 18 meters at different places. The walls are surrounded by a wide moat from the outside. The Chauhans added a number of gateways. Nothing remains of them but in historical accounts it is mentioned that there were at least 13 gateways including the Badaun Gate which was the main thoroughfare in the city. You can also find ruins of another gate named Hauz-Rani if you venture towards the western side of this fort. The fort also has a very big statue of Pirthviraj Chauhan, the last Hindu King of Delhi.