Mahabubnagar or Mahboobnagar (Urdu: محبوب نگر) is the biggest town in Mahabubnagar District of Andhra Pradesh, India. The city of Mahabubnagar is located at a distance of 100 km from Hyderabad. Formerly known as Rukmammapeta and Palamoor, it was named as Mahabubnagar on 4 December 1890, in the honour of Mir Mahabub Ali Khan Asaf Jah VI, the Nizam of Hyderabad (1869-1911 AD). It has been the headquarters of the district since 1883 AD. Mahabubnagar is bordered with River Tungabhadra in the south and surrounded by the Nalgonda, Hyderabad, Kurnool, Raichur and Gulbarga districts. It is believed that the Golconda diamonds including famous "Kohinoor" diamond came from Mahabubnagar district.[citation needed] It is the headquarter of Mahabubnagar District. It is also known by its erstwhile name of Palamoor. It is 100 km southwest of the state capital Hyderabad.