Kallimalai Peak (G.O. (P) No.65/2003/F&WLD dated Thiruvananthapuram, 20th December 03) (1615 M) it is bounded by mountain ridges of over altitude and toward the west it expands into a high plateau. From this level the altitude drops steeply to the deepest point of the reserve, the 100 metre valley of the Pamba River. The highest peak in the park is the high Kottamala, the southernmost peak in India higher than . The Periyar and Pamba Rivers originate in the forests of the reserve.