Tamil Nadu has a wealth of flora and fauna and some of its major wildlife sanctuaries like Mudumalai and Anaimalai(Indira Gandhi W.S) are situated in the hills of the Western ghats which is the habitat of elephants, tigers, bisons and a variety of monkey and deer. Of the 3000 and more plant species found in Tamil Nadu, a majority are found in the mixed deciduous forests of this region. One of the most noteworthy flowers is the Kurinji of Kodaikkanal which blooms once in 12 years.

Cinchona from which quinine - a drug for treating malaria - is extracted, and eucalyptus grow abundantly in the Nilgiris. Forests of medicinal herbs are found in Palani hills and Courtallam. Palmyrah trees grow by the thousands in Tirunelveli and its products are used as raw materials for several cottage industries. Rubber is the main plantation crop in Kanniyakumari and the more exotic sandalwood grows, though not in very large numbers, in the Javadhu hills of Vellore district. The perennial river of the state is the Cauveri which originates in Coorg in the neighbouring Karnataka.

The fertile Coromandel plains are irrigated by the Kaveri and its delta in Thanjavur - Nagapattinam region is known as the granary of Tamil Nadu. The other rivers in the state are the Palar, Pennar, Vaigai and Tamiraparani. The arid, desert-like land in the state is confined to a small area in Tirunelveli district and is known as the Palai.

The coastal Tamil Nadu comprises the Coromandel coast which has its northern half and the Fisheries coast which is the southern half. Mylapore, Poompuhar and Mamallapuram were the famous ancient ports on the Coromandel from where merchant ships sailed to Rome, Greece and the far east.

There are mangrove forests at Pichavaram and prominent bird sanctuaries at Pulicat Lake and Vedanthangal, though the latter is not on the coast itself. Once famous for its pearls, the Fisheries coast is a major tourist attraction since it has some of the most important pilgrim centres in India.