The Palani Hills are an eastward extension of the Western Ghats ranges, which run parallel to the west coast of India.

The Palani Hills adjoin with the high Anamalai range on the west and extend east into the plains of Tamil Nadu, covering an area of 2,068 square kilometres (798 sq mi).

The Palani Hills Wildlife Sanctuary and National Park is a proposed protected area in Dindigul District, Tamil Nadu.

[7] In the early 1990s, the Tamil Nadu Forest Department submitted a proposal to the State government to protect much of the Palani Hills by declaring the area a wildlife sanctuary or a national park.

[10] On 13 August 2012, in an apparent change away from plans for notification of parts of the Palani Hills as a separate wildlife sanctuary, the Tamil Nadu Gazette notification attached parts of Kodaikanal and Dindigul divisions of reserve forests to the buffer zone of Annamalai Tiger Reserve.

The villages and hamlets that now form part of the Palani Hills buffer zone are Poondi, Mannavanur, Kilavarai, Polur, Kavunchi, Kumbur, Kilanavayal, Kukkal, Pazhamputhur and Puthurpuram.

[11][12] The increasingly important economic role of Eco-tourism, including trekking, hiking, camping, mountaineering, rock climbing and bird watching may help the local populace to welcome this new Protected area.

The range lies between the Cumbum Valley on the south, which is drained by the Vaigai River and its upper tributaries, and the Kongunadu region to the north.

[16] The lower elevations of the Palani Hills, between 250 and 1,000 m (820–3,281 ft), are part of the South Western Ghats moist deciduous forests ecoregion.

[17] The Palani Hills are formed of pre-Cambrian gneisses, charnockites and schists; they are among the oldest mountain ranges in India.

[18] The park is an eastward extension of the Western Ghats hills formed by separation of the India-Madagascar-Seychelles blocks of East Gondwana in the Early Cretaceous period about 120 million years ago.

The ten most prominent peaks are: The hill station of Kodaikanal stands in a 2,195 m (7,202 ft) high basin at the southern edge of the central part.

[21] The Tamil Nadu Department of Geology and Mining has completed detailed Geo-Technical Studies of the Palni Hills determining moderate to high landslide danger in much of the area.

Some of the prominent falls associated with the park are: (Distances are referenced from km 0.0 at the bund (dam) on northeast end of Kodaikanal lake at .)

Generally, as one proceeds from the Kerala border in the west to the foothills in the east, average rainfall decreases and temperature increases.

[30] Many native tribals in the Palani Hills have partially assimilated modern culture but are marginalized on the fringes of society.

Forest Department officials are studying survey data to estimate the local tiger population based on indirect evidence like pug marks, scats and scratches.

[37]Amphibians and reptiles: Several little-known and endemic species of amphibians like Raorchestes dubois, Ghatixalus asterops, Micrixalus nigraventris, Indirana leptodactyla, Nyctibatrachus deccanensis and reptiles like Salea anamallayana, Hemidactylus anamallensis, Kaestlea palnica, Kaestlea travancorica, Ristella rurkii, Platyplectrurus madurensis, Teretrurus rhodogaster, Uropeltis pulneyensis, Uropeltis broughami, Uropeltis woodmasoni, Ahaetulla dispar, Boiga dightoni and Trimeresurus macrolepis occur in this sanctuary.

Plants: Moist areas exist along the ravines and in the sheltered pockets of high elevation shola forests around 2,000 metres (6,600 ft).

: a new species for the Palni hills first collected in April 2000,Actinodapohne bourneae: Laurel tree believed extinct (Botanical Survey of India).

[40] There is decreasing biodiversity, deforestation, grasslands destruction, monoculture tree plantations, and invasive exotic plant species in the park.

The Government of Tamil Nadu and several local NGO conservation groups are actively working to reduce some of these threats: A sum of Rs.1327.50 lakhs has been released for this purpose during 2006–2007.

Forest rest houses are available with advance reservation at Kodaikkanal, Poombarai, Kukkal, Kavunji, Berijam and Devadanapatty.