The Ponnaiyar River flows in the southern part of India. It originates in the southeastern slopes of the Chennakesava hills (situated at an altitude of 1000 metres above mean sea level) north west of Nandidurg in Kolar district of Karnataka. The Ponnaiyar River is also called the South Pennar or the Dakshina Pinakini. The river flows in the south direction and then in the east direction for four hundred kilometers (250 miles) through Tamil and Karnataka. The river finally surrenders in to the Bay of Bengal at Cuddalore.
The Ponnaiyar river basin is encircled by the Cauvery river basin in the west and south and Palar and Tondiar basins in the east and north respectively. The Ponnaiyar River is a transient river that flows only for a few weeks during the rainy season.