Geography of South India

South India is a peninsula in the shape of an inverted triangle bound

By the Arabian Sea on the west:

The Western Ghats run parallel to the Arabian Sea along the western coast and the narrow strip of land between the mountains and the sea forms the Konkan region. The Western Ghats continue south until Kanyakumari.

By the Bay of Bengal on the east:

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.

The Vindhya and Satpura ranges on the north:

The Narmada river flows westwards in the depression between the Vindhya and Satpura ranges, which define the northern, spur of the Deccan plateau. Both mountain ranges meet at the Nilgiri mountains.

The Nilgiris run along the borders of Tamil Nadu with northern Kerala and Karnataka, encompassing the Palakkad and Wayanad hills and the Sathyamangalam ranges, extending to the relatively low-lying hills of the Eastern Ghats on the western portion of the Tamil Nadu–Andhra Pradesh border, forming the Tirupati and Annamalai hills.