The Kodavanar, is a river in the Palni Hills in Tamil Nadu.
At the northern side of Kamarajar Lake are the Kannivadi Hills up to approximately 800 metres (2,600 ft) high. In the west is the so-called northern slope of the Palani Hills up to 1,500 metres (4,900 ft) high. There is a river from Pandrimallai, named the Karuvalli Ar (up-stream) and Kūlal Ar (down-stream). The Kūlal Ar enters in the northwest side of Kamarajar Valley where Palani Hills and Kannivadi Hills meet each other. On his way down the Kūlal Ar passes two waterfalls, many small cascades and ponds. The other river is called the Kodavanār River. It is a run off from Thandikudi and passes Pannaikadu and enters the Kamarajar Lake in the southwest side of the valley .