The ruins of this fort are located on a small hill which once stood on the bank of the river Yamuna.Legend has it that the fort marked the site of Indraprastha ,the magnificent capital of the Pandavas, though the construction was carried out by Sher Shah Suri any time between 1538 to 1545 A. D. The structure houses a mosque which has a double storeyed octagonal tower. It is said that the Mughal King Humayun fell from the tower accidently and died.

 There are three Gates to this fort. Today entrance is through the Bara Darwaza. The South Gate is called the Humayun Darwaza, probably because Humayun built it or because the tomb of Humayun is visible from here. The third gate is the Talaqi Darwaza. Recent excavations in the fort has revealed painted grey pottery which date back to 1000 BC. Such and many more findings inside the fort have proved the location to be inhabited since the early civilizations. In fact there was a village inside the fort till 1913 called Indrapat which is very close to Indraprastha adding credibility to the theory of Mahabharata having taken place here.

Inside the fort Qila Kuhna Masjid which is one of the finest example of architectural style being used in those days. The Masjid was built by Sher Shah in 1541 and it seems that there was an attempt to build the whole structure in Marble. But the scarcity of marble forced the use of Redsand stone. This mixture was accidental forced or intended we do not know, nevertheless the combination adds a different look to the structure. The inner west wall of the Masjid has five arched openings and which are richly ornamented in white and black marbles.

At the foot of the hill is the lake where the Delhi Tourism has arrangements for boating and also organises a Sound and Light Show.