The national Park "Northern ridge of the Sierra Madre" is one of the largest protected rain forest in the Philippines. It is situated on the territory of 359 thousand hectares in the Western part of the province of Isabela. Two intact primeval forests of Luzon's Sierra Madre is the largest. The other is located on the territory of the mountain range of the Cordillera. The Park was founded in 1997 to protect these lands from predatory logging. Along with nearby protected area "Penablanca" it covers an area greater area of Switzerland. The Park is also known as Complex Palanan or Reserve Palanan the name of the highest mountain.

The national Park "Sierra Madre" occupies the Northern part of the eponymous mountain range, which occupies a total area of 1, 7 million ha. In the North the river flows Dictan, and the southern boundary of the Park is the river Disapora. To the West lay the valley of the Cagayan, and in the East coast Park washes Philippine sea.

Most of the Park is 287 thousand hectares is land and the remaining 71 thousand hectares covers the sea. The mountainous landscape of the Park, from small hills to the highest peak, reaching a thousand meters – so, mount Division has a height of 1311 metres, the mountain of the cross – 1672 meters, and the mountain Palanan – 1184 meters. Despite the fact that part of the Park of the Sierra Madre in the past been cutting down, today we can still see the lush virgin forest.

The Park has several species of animals and plants under threat of extinction, and species that are endemic, not found anywhere else in the world. In the forests of the Sierra Madre can be found up to 45% of plant species native only to the Philippines, and more than 50% of animal species – the indigenous inhabitants of these places. The lowlands are covered with pristine rain forest, and the mountains – a typical Alpine vegetation. On the coast you can see mangroves and coastal vegetation, and under water – the whole field of algae and coral reefs of incredible beauty. The Park is home to rare bird species, including 6 species of Philippine eagles and reptiles Philippine water lizard, estuarine crocodile, monitor lizard gray, green sea turtle, Caretta Caretta turtles and hawksbill turtle.

The national Park "Sierra Madre" is considered the most important protected area of the Philippines. It is the largest Park in the country and one of the richest in species and ecological diversity.