About 400m south-east of the flagstaff tower lies the
Chauburji-Masjid, a double-storeyed structure with a central chamber
surrounded by a small chamber on each side. There is a 'minhrab' or prayer
niche, in the west wall of the western chamber.
The upper storey of the mosque is occupied by a domed chamber on the southwest corner, other such chambers having disappeared. It drives its name, meaning the 'mosque with four towers', from its original four domes. It was repaired and altered in the late Mughal times.
It was built by Feroze Shah Tughluq, evidently as a mausoleum and probably formed part of his palace called Kuskh-i-Shikar or Kushk-i-Jahan-Numa by contemporary writers. Another surviving part of his palace situated over here is Pir-Ghaib .