Erode district(formerly Periyar district) is a district in the Kongu Nadu region (western part) of the Indian state of Tamil Nadu. It was the largest district by area in the state before the formation of Tiruppur district and the headquarters of the district is Erode. Periyar district was a part of Coimbatore District before its division into two on September 17, 1979 and was renamed as Erode District in 1996. As of 2011, the district had a population of 2,251,744 with a sex-ratio of 993 females for every 1,000 males, much above the national average of 929.