Palar is a river of southern India. It rises in the Nandi Hills in Chikkaballapura district of Karnataka state, and flows in Karnataka, in Andhra Pradesh and in Tamil Nadu before reaching its confluence into the Bay of Bengal at Vayalur about south of Chennai. It flows as an underground river for a long distance only to emerge near Bethamangala town, from where, gathering water and speed, it flows eastward down the Deccan Plateau. The Towns of Bethamangala, Santhipuram, Kuppam, Ramanaickenpet, Vaniyambadi, Ambur, Melpatti, Gudiyatham, Pallikonda, Melmonavoor, Vellore, Katpadi, Melvisharam, Arcot, Ranipet, Walajapet, Kanchipuram, Walajabad, Chengalpattu, Kalpakkam, and Lattur are located on the banks of the Palar River. Of the seven tributaries, the chief tributary is the Cheyyar River.