The topography of Tamil Nadu is delightfully varied and diverse. Of the 1,30,058 sq km land area, 17.6 % is covered with forest area. Drylands are bestowed with dry-deciduous forests, thorn forests, scrubs, and mangroves. The Western Ghats and a few cooler regions are endowed with moist deciduous, wet evergreen forests, sholas, and grasslands.
Tamilnadu is rich in flora and fauna. Some of the major wildlife sanctuaries of Tamilnadu like Madumalai and Annamalai (or Indira Gandhi Wildlife Sanctuary) are situated in the Western Ghats. These hills are ideal havens for elephants, tigers, bison, monkeys, and deer. Of the 3,000 and more plant species found in Tamilnadu, a majority is found in the mixed deciduous forests of this region. One of the most noteworthy flowers is the Kurinji of Kodaikanal, which blooms once in 12 years. Cinchona, from which the anti-malarial drug quinine is extracted, and the medicinal eucalyptus grow abundantly in the Nilgiri hills. Forests of other medicinal herbs are found in Palani hills and Courtallam.
Tamil Nadu has 5 declared National Parks with a total area of over 307.84 km2, covering only 0.24% of the state.
- Indira Gandhi National Park
- Mudumalai National Park
- Mukurthi National Park
- Gulf of Mannar Marine National Park
- Guindy National Park
- Palani Hills National Park 736.87 km2 is a proposed upgrade of the Kodaikanal Wildlife Sanctuary being established in 2008.
- Grizzled Squirrel Wildlife Sanctuary, a 485 km2 Giant Squirrel Sanctuary near Srivilliputhur, in Virudhunagar district consisting of mainly dry deciduous forests with patches of tropical evergreen forests, semi-evergreen forests, moist mixed deciduous forests, and grassland. Grizzled Giant Squirrel, Flying Squirrel, Tree Shrew, Elephant, lion-tailed macaque, Nilgiri Tahr, mouse deer, barking deer and many species of birds may be seen.
- Indira Gandhi Wildlife Sanctuary is contiguous with Indira Gandhi National Park in Coimbatore District.
- Kalakkad Wildlife Sanctuary in Tirunelveli District is part of the Kalakkad Mundanthurai Tiger Reserve. This sanctuary is famous for Lion-tailed macaque. All four species (common Langur, Nilgiri Langur, Bonnet Macaque, and lion-tailed Macaque) can be seen. Other animals include Nilgiri tahr, sambar, sloth bear, gaur, Indian elephant, tiger, flying squirrel, panther, Dhole, pangolin and a variety of birds and reptiles.
- Mundanthurai Sanctuary 282.08 km2 in Tirunelveli District, is part of Kalakkad Mundanthurai Tiger Reserve.
- Kanyakumari Wildlife Sanctuary is a 457.78 km2 tiger habitat in Kanyakumari district declared a sanctuary in February 2008.
- Mudumalai Wildlife Sanctuary in Nilgiris district is contiguous with Mudumalai National Park. It consists of 217.76 km2 primarily moist deciduous forest which becomes dry deciduous towards Bandipur including mainly mixed forests with bamboos. Animals including Elephant, Gaur, Sambar, Chital, Dhole Panther, Tiger, Sloth bear, Python, Barking deer, Four-horned antelope, common Langur, Otter, Crocodiles and a variety of birds and reptiles may be seen.
- Sathyamangalam Wildlife Sanctuary in Erode district, 1,411.6 km2, the largest wildlife sanctuary in Tamil Nadu, was declared a sanctuary in 2008.