The Palk Strait is a 40-85 mi (64-137 km) wide strait that lies between India and Sri Lanka between Dhanushkodi, near Rameswaram in the state of Tamil Nadu in India, and Talaimannar in the Mannar island in Ceylon. It is studded at its southern end with a chain of shoal reefs that are collectively called Adam's Bridge, Pamban Bridge (India), and Mannar Island (Sri Lanka) is found at its southern end. The strait's treacherous waters are usually avoided by most ships. It receives several rivers, most notably the Vaigai .

Like the English Channel, the Palk Strait has been taken up as a challenge by many long-distance swimmers.

The Hindu epic Ramayana recounts how Lord Rama with the help of an army of Vanaras or monkeys built a bridge of stones across the sea to Lanka to rescue his bride Sita from the Asura king Ravana. Some Christians believe this mythical bridge to be Adam's Bridge. However, no conclusive archaeological evidence has been found to this effect.