structural:expansion
Geography

Tamil Nadu covers an area of 130,058 km (50,216 sq mi) and is the tenth-largest state in India. Located on the south-eastern coast of the Indian peninsula, Tamil Nadu is straddled by the Western Ghats and Deccan Plateau in the west, the Eastern Ghats in the north, the Eastern Coastal Plains lining the Bay of Bengal in the east, the Gulf of Mannar and the Palk Strait to the south-east, and the Laccadive Sea at the southern cape of the peninsula. Politically, Tamil Nadu is bound by the Indian states of Kerala, Karnataka, and Andhra Pradesh, and the union territory of Puducherry. It shares an international maritime border with the Northern Province of Sri Lanka at Pamban Island. The Palk Strait and the chain of low sandbars and islands known as Rama's Bridge separate the region from Sri Lanka, which lies off the southeastern coast. The southernmost tip of mainland India is at Kanyakumari where the Indian Ocean meets the Bay of Bengal and the Arabian Sea.

The Western Ghats run south along the western boundary with the highest peak at Doddabetta (2,636 m (8,648 ft)) in the Nilgiri Hills. The Eastern Ghats run parallel to the Bay of Bengal along the eastern coast and the strip of land between them forms the Coromandel region. They are a discontinuous range of mountains intersected by Kaveri river. Both mountain ranges meet at the Nilgiri mountains which run in a crescent approximately along the borders of Tamil Nadu with northern Kerala and Karnataka, extending to the relatively low-lying hills of the Eastern Ghats on the western portion of the Tamil Nadu–Andhra Pradesh border. The Deccan plateau is the elevated region bound by the mountain ranges and the plateau slopes gently from west to east resulting in major rivers arising in the Western Ghats and flowing east into the Bay of Bengal.

The coastline of Tamil Nadu is 1,076 km (669 mi) long, and is the second longest state coastline in the country after Gujarat. There are coral reefs located in the Gulf of Mannar and Lakshadweep islands. Tamil Nadu's coastline was permanently altered by the Indian Ocean tsunami in 2004.