Tamil Nādu, state in southern India, bordered on the north by Andhra Pradesh state, on the northwest by Karnātaka state, on the west by Kerala state, and on the east and south by the Bay of Bengal and the Indian Ocean. Occupying the extreme south of the Indian peninsula, Tamil Nādu has an area of 130,058 sq km (50,216 sq mi).Most of Tamil Nādu is hilly. To the north lie the Nīlgiri Hills, covering an area of 2,500 sq km (1,000 sq mi) and rising to 2,600 m (8,500 ft) in places. To the west lie the Western Ghats and in the south, the Anamalai Hills. East of the hills lie the plains and the flat alluvial coast, with deltas at the mouths of the major rivers. The Kāveri (Cauvery) River and its tributaries are Tamil Nādu's most important sources of water for irrigation and power generation. Other rivers running through the state are dry during part of the year because the hills create a rain shadow effect that blocks precipitation. The climate is essentially tropical, with the plains being hotter than the uplands. During the October to December monsoonal season, the coastal area often suffers severe damage from cyclones sweeping in from the eastern Indian Ocean. Rainfall averages between about 630 and 1,900 mm (about 25 and 75 in) a year. The hill areas tend to receive the most rain. Tamil Nādu, on the whole, is much drier than Kerala to the west.
Tamil Nādu had a population of 62,110,839 in 2001, with an average population density of 478 persons per sq km (1,238 per sq mi). Chennai (formerly Madras), the capital, is India's fourth largest city and a major port and industrial center. Madurai, famous for its temples, is now also an important industrial center. Ethnically, Tamil Nādu's population has changed little since the earliest settlements; the vast majority of people are Dravidians. Groups of tribal people live in the Nīlgiri Hills, among them the Todas, Badagas, Kotas, Kurumbas, and Irulas. More than 85 percent of the population speaks Tamil, which is the state's official language; The Tamil language is one of the oldest literary languages in India; some Tamil poetry dates back almost 2,000 years. Most of the population is Hindus, with small minorities of Muslims, Jains, Parsis, and Christians. Throughout Tamil Nādu there is a vital tradition of music and dance;