Plateaus and basins predominate the Ras Koh Hills with an average elevation of 600 metres, but in areas, the hills can reach elevations up to 3,000 metres. The Ras Koh Hills are composed of granite, are carved out by innumerable channels, but the arid climate restricts rain and for the most part leaves these channels dry. Although little water reaches the low-lying basins, numerous alluvial fans are found in the area.