Theni District was formed by bifurcation from erstwhile Madurai District. It is located in the western region of the state of Tamil Nadu. It is bounded by Dindigul District to the north, Virudhunagar District to the southwest, Madurai District to the east and Idukki District in Kerala to the west. The city of Theni is the district headquarters.
The economy of the district relies mainly on agriculture. The main produce of the district are cotton, cardamom, garlic, grapes, mango, and sugarcane. Cotton spinning and sugar mills are the major industries in the district.