The Cheyyeru is formed by the confluence of the rivers Bahuda and Puncha that originate in the Chittoor district of Andhra Pradesh. The two streams join at Rayavaram to form the Cheyyeru which then flows for 87 km before joining the Pennar as a right bank tributary at Gundlamada in the Sidhout taluk of Cuddapah district, draining a total area of 7,325 km2. The Gunjana river is a tributary of the Cheyyeru and along the Gunjana valley several paleolithic settlements have been discovered. There are several gorges on the river including one after the confluence of its headstreams and the Balarajupalle gorge. The Cheyair series of rocks in the Cudappah rock system of the Eastern Ghats, consisting largely of shales, is named after the Cheyyeru river.