Silent Valley is rectangular, twelve kilometres from north to south and seven from east to west. Located between 11°03' to 11°13' N (latitude) and 76°21' to 76°35' E (longitude) it is separated from the eastern and northern high altitude plateaus of the (Nilgiris Mountains) by high continuous ridges including Sispara Peak (2,206 m) at the north end of the park. The park gradually slopes southward down to the Palakkad plains and to the west it is bounded by irregular ridges. The altitude varies from 658 m to 2328 m at Anginda Peak, but most of the park lies within the altitude range of 880 m to 1200 m. Soils are blackish and slightly acidic in evergreen forests where there is good accumulation of organic matter. The underlying rock in the area is granite with schists and gneiss, which give rise to the loamy laterite soils on slopes.