Erode District is one of the 38 districts in the state of Tamil Nadu in India. It was the largest district by area in the state before the formation of Tirupur District in 2009. The headquarters of the district is Erode. It is divided into two revenue divisions, Erode and Gobichettipalayam, and is further subdivided into 10 taluks. Erode District was a part of Coimbatore District before its division into two on 17 September 1979. It covers an area of , and as of 2011, had a population of 2,251,744.
The region belonging to present-day Erode District was ruled successively by several South Indian dynasties, including the Cheras, Cholas and Pandyas. During the first millennium, it was under the rule of the Chera Dynasty and various other rulers. Between the 10th to 12th centuries, the region was part of the larger Chola Empire. The region became part of Vijayanagara empire in the 14th century, then under the Nayaks of Madurai until the 17th century. Under the Madurai Nayaks, the Polygar system of administration was established. The Polygar system continued after the region became part of the Kingdom of Mysore in the mid-17th century.
The Polygar chieftain Dheeran Chinnamalai, a governor of the region, played a major role in the early struggle for Indian Independence in the late 18th-century Polygar Wars against the British East India Company. After the Polygar and Mysore Wars in the late 18th century, the area came under the control of the British until the achievement of Indian independence in 1947. It was a part of the erstwhile Coimbatore district until its split in 1979.
According to the 2011 census, Erode District had a population of 2,251,744 with a sex-ratio of 993 females for every 1,000 males, above the national average of 929. A total of 195,213 were under the age of six, constituting 99,943 males and 95,270 females. Scheduled Castes and Scheduled Tribes accounted for 16.41% and 0.97% of the population, respectively. The literacy rate of the district was 66.29%, compared to the national average of 72.99%.