The Kalrayan Hills (Tamil : கல்வராயன் மலை) are a major range of hills situated in the Eastern Ghats of the southern Indian state of Tamil Nadu. Along with the Pachaimalai, Javadi, and Shevaroy hills, they separate the Kaveri River basin to the south from the Palar River basin to the north. The hills range in height from 2000 feet to 3000 feet and extend over an area of 1095 square kilometres.
The hills straddle a number of Tamil Nadu districts, extending northeast from the Salem District. The range serves as a boundary between the Salem and Villupuram districts. The Kalrayans are divided into two sections — the northern section, referred to as the Chinna ("little") Kalrayans, and the southern section, called the Periya ("big") Kalrayans. The Chinna Kalrayans average 2700 feet in height, while the Periya Kalrayans average 4000 feet.
The range as a whole is fairly smooth, with soil well-suited for plant growth. Scrub jungles reach up to 400 metres in altitude, while deciduous forests can be found between above 800 metres. Sholas, a type of high-altitude stunted evergreen forest, can be found growing on isolated plateaus. Though the forest stand is growing, due to "habitat uniqueness, human impacts and cultural tradition," conservation efforts are needed.
- Sakthivel, R., M. Manivel, A. Alagappa Moses (2003). Application of Remote Sensing data for Delineation of Ground Water potential zones in the Kalrayan Hills, Tamil Nadu. GISdevelopment.net. Retrieved 2007-03-16.
- "Pachaimalai Hills". Encyclopædia Britannica. Encyclopædia Britannica Online. 2007. Retrieved 2007-03-15.
- Nazer, M. (2004). A Study of Land Alienation and Indebtedness among Tribals in Tamil Nadu, Kerala and Karnataka states (PDF). Planning Commission, Government of India. Retrieved 2007-03-15.
- Kadavul, K., N. Parthasarathy (19 April 1999). "Structure and composition of woody species in tropical semi-evergreen forest of Kalrayan hills, Eastern Ghats, India". Trop. Ecol. 40 (2): 247–260. ISSN 0564-3295. Retrieved 2007-03-16.