Nili Masjid is located in Delhi within the Hauz Khas Enclave. It was built during the reign of Sikandar Lodi between the years 1505-06 by a Kasaumbhil, a nurse by profession. She served as a nurse of Fath Khan, the son of Khan I Azam Masnad, the governor of Delhi. It is a rubble built mosque but has been well plastered. Presently only the central chamber of the mosque is all that is left. It has three arched openings and is surmounted by a dome. One can also see an inscription in the central arch of the mosque that depicts the date of its construction. The mosque has been given the name `Nili Masjid` because the facade above the chhajja i.e. lintel has been adorned with blue tiles. Nili Masjid is an Archaeological Survey of India protected monument that has been constructed on a 5 feet high dais. It and has three gates and eight pillars. Presently the mosque is under renovation work.

Towards the southern direction of the Nili Masjid lies the ruin of an Idgah. It has rubble built walls on the western side that has almost a series of eleven mihrabs. Judging from its structure it seems that it had been a place of worship as well as a battlefield. There is an inscription carved on the southern bastion of the structure which states that the mosque had been built by Iqbal Khan around 1404-05 after the invasion of Timur. Iqbal Khan was a powerful noble during the reign of Mahmud Tughlaq`s reign. There is tower located in the vicinity of Nili Masjid. It is known as Chor Minar. It is rubble built tapering tower that had been built during the Khilji period. The tower has been set on a raised platform. It is adorned with a staircase in its interior side. It is believed that earlier it might have served as a watchtower.

Nilli Masjid is open on all days and can be easily reached. Tourists can either take local buses from various points within the city to reach the monument located in South Delhi, or they can hire auto rickshaws and taxis or take the metro rail. The nearest Railway Station is located at Nizamuddin Railway Station, the nearest metro station is the Central Secretariat and the nearest International Airport is the Indira Gandhi International Airport.