Ponniar River, 331 km long, takes it birth in the eastern slopes of Chennakesa Hills, north-west of Nandi Drug and flows towards the south-east. The river flows through the districts of 416853}Krishnagiri,
Dharmapuri,
Vellore and
Cuddalore and drains into the
Bay of Bengal near
Cuddalore town.
Many irrigation projects are constructed across this river such as the
Kelavarapalli Dam and Sathanur Reservoir.