Secunderabad is the twin city of Hyderabad in the Indian state of Telangana. Named after Sikandar Jah, the third Nizam of the Asaf Jahi dynasty, Secunderabad was established in 1806 as a British cantonment. Although both the cities are together referred to as the twin cities, Hyderabad and Secunderabad have different histories and cultures, with Secunderabad having developed directly under British rule until 1948, and Hyderabad as the capital of the Nizams' princely state of Hyderabad.
Geographically divided from Hyderabad by the Hussain Sagar lake, Secunderabad is no longer a separate municipal unit and has become part of Hyderabad's Greater Hyderabad Municipal Corporation. Both cities are collectively known as Hyderabad and together form the sixth-largest metropolis in India. Being one of the largest cantonments in India, Secunderabad has a large presence of army and air force personnel.