Thyagaraya Nagar, commonly known as T. Nagar, and historically known as East Mambalam, is a very affluent commercial and residential neighbourhood in Chennai, Tamil Nadu, India. It is surrounded by Nungambakkam in the North, Teynampet in the East, Nandanam in the South-East, C.I.T. Nagar in the South and West Mambalam and Kodambakkam in the West. The stretch between Duraiswamy Road and T. Nagar Bus Stand has some of the costliest real estates in Chennai. It was constructed between 1923 and 1925 by the Madras Presidency government of the Raja of Panagal as a part of town planning activities initiated according to the Madras Town Planning Act of 1920. The town was named after P. Thyagaraya Chetty. The streets, parks and localities in the new neighbourhood were named after important officials in the provincial government.

Nungambakkam is a locality in downtown Chennai, India. The neighborhood abounds with multi-national commercial establishments, important government offices, foreign consulates, educational institutions, shopping malls, sporting facilities, tourist spots, star hotels, restaurants, and cultural centers. Nungambakkam is also a prime residential area in Chennai. The adjoining regions of Nungambakkam include Egmore, Chetpet, T. Nagar, Kodambakkam and Choolaimedu.