Perambalur (Tamil: பெரம்பலூர் மாவட்டம்) is an administrative district in the state of Tamil Nadu in India. The district headquarters are located at Perambalur. The district occupies an area of 1,752 km² and had a population of 565,223 with a sex-ratio of 1,003 females for every 1,000 males in 2011.
Perambalur district is a centrally located inland district of Tamil Nadu, spread over 3,69,007 ha, which was trifurcated from the erstwhile composite Tiruchirappalli district and was formed on 1 November 1995. The district is bounded by Cuddalore district in the north, Tiruchirappalli district in the south, Thanjavur in the east and Namakkal and Tiruchirappalli districts in the west. The total geographical area of the district is 3,69,007 ha, and net sown area and gross sown area are 2,16,422 ha and 2,37,136 ha, respectively. The net area under irrigation is 71,624 ha.
The district lies in the Southern plateau & hill zone of Agro-climate regional planning with characteristics of semi-arid climate. The soil is predominantly red loamy and black soil. The normal rainfall of the district is 908 mm which is less than 946.9 mm, the normal rainfall of the State. The precipitation during northeast monsoon, southwest monsoon and remaining winter & hot weather period account for 52%, 34% and 14% of annual rainfall, respectively.
Cauvery is the major river flowing in the region and the composite district has a canal system covering just 47 km stretch and ayacut of 11,610 ha. The ground water resource through tubewells and wells contribute nearly 68% of irrigated area command. The major crops grown in the district are paddy, groundnut, sugarcane and millets. Cashew is the major plantation crop. Now the major cultivation is small Onion, totally 24% in Tamil Nadu i.e. first place in Tamil Nadu. The Onion cultivation villages are Nakkasalem, Ammapalayam, Siruvayalur, Chettikulam, Kalarampatty, Esanai, Arumbavur.