Coordinates: 28°36′36″N 77°14′42″E / 28.610°N 77.245°E
Purana Qila (Old Fort) is one of the oldest forts in Delhi. Its current form was built by Sher Shah Suri, the founder of the Sur Empire. Sher Shah raised the citadel of Purana Qila with an extensive city-area sprawling around it. It is believed that the Purana Qila was still incomplete at Sher Shah's death in 1545, and was perhaps completed by his son Islam Shah , although it is not certain which parts were built by whom.
Excavations carried out by Archaeological Survey of India (ASI) at Purana Quila in 1954-55 (trial trenches) and again 1969-1973 by its Director, B B Lal, have unearthed Painted Grey Ware dating to 1000 BCE.
The fort was the inner citadel of the city of Din Panah during Humayun's rule who renovated it in 1533 and completed five years later. The founder of the Suri Dynasty, Sher Shah Suri, defeated Humayun in 1540, naming the fort Shergarh; he added several more structures in the complex during his five-year reign. Purana Qila and its environs flourished as the "sixth city of Delhi".
When Edwin Lutyens designed the new capital of British India, New Delhi, in the 1920s, he aligned the central vista, now Rajpath, with Purana Qila. During the Partition of India, in August 1947 the Purana Qila along with the neighbouring Humayun's Tomb, became the site for refuge camps for Muslims migrating to newly founded Pakistan. This included over 12,000 government employees who had opted for service in Pakistan, and between 150,000–200,000 Muslim refugees, who swarmed inside Purana Qila by September 1947, when Indian government took over the management of the two camps. The Purana Qila camp remained functional till early 1948, as the trains to Pakistan waited till October 1947 to start.