The Northern Sierra Madre National Park consists of forests in the northern half of the 1.7-million-hectare Sierra Madre mountain range. The park lies east of the province of Isabela. The part is furthermore, the most extensive area of preserved rainforest in the Philippines at 359,486 hectares. It is the larger of 2 remaining areas of intact primeval forest in Luzon. Its landscape is hilly to mountainous, with the Sierra Madre Mountain Range running through it. While many parts of the forest cover of the Northern Sierra Madre Mountains have been heavily logged in the past, the interior still consists of lush virgin forest. The park is home to a large number of endangered and protected animal and plant species, which are indigenous to the Philippines.