
The Eastern and Western Ghats meet in Tamil Nadu and run along the state's eastern and western borders. Hill stations like Udhagamandalam (Ooty), Kodaikanal, Kothagiri and Yercaud are situated in this hilly region. It is interesting to note that there are only two major gaps (Palakkad gap and Shencottah gap) into the long chain of hills that border western Tamil Nadu. In a marked contrast to the low rocky hills of the Eastern Ghats, the hills of the Western Ghats have dense forests. This region receives plentiful rainfall and the scenic valleys here are dotted with tea, spice and coffee plantations. The upper reaches of Eastern Ghats are famous for their fruit orchards, banana and coffee plantations.
Being a tropical land, Tamil Nadu is rich in various types of flora and fauna. Wildlife sanctuaries like Mudumalai and Anaimalai are habitats of elephants, tigers, bison and a variety of monkey and deer. There are more than 3000 plant species that are found in Tamil Nadu and a majority of them are in the mixed deciduous forests of the region. A variety of medicinal herbs are found in the Palani hills and Courtallam. Rubber is the main plantation crop in Kanyakumari region and the more exotic sandalwood grows in the Jawadhu hills of Vellore district.
Cauvery is the most important river of Tamil Nadu. It is a perennial river and originates in the Coorg district of the neighboring Karnataka state. Other important rivers in the state are the Palar, Vaigai, Pennar and Tamiraparani. The coastal Tamil Nadu comprises of the Coromandel Coast. There are mangrove forests at Pichavaram and important bird sanctuaries at Pulicat Lake and Vedanthangal.