The Kalrayan Hills form a major part of Eastern Ghats of the southern Indian state of Tamil Nadu. It lies on the western side of the Kallakurichi taluk. The Pachaimalai, Javadi and Shevaroy and the Kalrayan hills flow between the Kaveri River basin in the north and the Palar River basin to the south.

Spread over an area of 1095 square kilometers, the height of the hills vary from two thousand feet to three thousand feet above mean sea level. The hills cover a number of districts of Tamil Nadu extending northeast from the Salem district. It separates the district of Salem and Villupuram districts. The hill range is divided into two portions, the northern portion is called Chinna (little) Kalrayans and the southern portion is called Periyar (big) Kalrayans. The average height of the Chinna Kalrayans is 2700 feet while that the Periya Kalrayans is 4000 feet. The vegetation of the hills vary according to the height with scrub jungles at a height of four hundred metres and deciduous forests at a height of eight hundred metres above mean sea level.

The region surrounding the hills was the seat of Vijaynagar empire. The karalar tribe community dominated this place from that period onwards. The hills offer exciting oppurtunities for trekking.

The Kalrayan Hills is spread over an area of 1095 square kilometers, covering a major part of the Eastern Ghats in Tamil Nadu.