Cordillera Central (Luzon) Sierra Madre Mountains, the longest mountain range in the country, through the Caraballo Mountains in Nueva Vizcaya province. During Spanish colonial period, the whole range was called "Nueva Provincia", (New Province). The Cordillera Central is the highest mountain range in the Philippines. It comprises about 1/6 of the whole Luzon island with a total area of . The highest mountain in the range, Mount Pulag, is also the highest mountain on Luzon Island at . It is officially the third highest mountain in the country after Mount Dulang-dulang and Mount Apo on Mindanao Island, the second largest island of the
Mount Apo Blue Lake" and Lake Venado, a well-known mountaineers camping site and a stopover towards the peak. Lake Macadac and Lake Jordan are found in the summit grassland. Rivers – Mt. Apo has 19 major rivers and 21 creeks draining its 8 major watersheds (PASAlist.1992). Out of the 19 major rivers, only two has studies as reported by SEA-BMB consultants for the Mt. Apo Geothermal Project Environmental Impact Assessment 1991. According to the report, there are two river ecosystems draining the geothermal site namely: (1) Marbel-Matingao river ecosystem- characterized by narrower river channels at highly elevated areas, much faster water flow,