Sierra Madre
View south of the northern Sierra Madre from the peak of Mount Cagua in Cagayan
Highest point
PeakMount Guiwan
Elevation1,915 m (6,283 ft)
Length540 km (340 mi) North to south
Width56 km (35 mi) east to west
Area16,260 km2 (6,280 sq mi)
Sierra Madre is located in Philippines
Sierra Madre
Sierra Madre
Location of the center of the range in the Philippines
Range coordinates16°3′N 121°35′E / 16.050°N 121.583°E / 16.050; 121.583
Borders onPacific Ocean

The Sierra Madre is the longest mountain range in the Philippines. Spanning over 540 kilometers (340 mi), it runs from the province of Cagayan down to the province of Quezon, forming a north–south direction on the eastern portion of Luzon, the largest island of the archipelago. It is bordered by the Pacific Ocean to the east, Cagayan Valley to the northwest, Central Luzon to the midwest, and Calabarzon to the southwest. Some communities east of the mountain range, along the coast, are less developed and so remote that they could only be accessed by taking a plane or a boat.[1]

The country's largest protected area, the Northern Sierra Madre Natural Park, is situated at the northern part of the range in the province of Isabela. The park is in the UNESCO tentative list for World Heritage List inscription. Environmentalists, scholars, and scientists have been urging the government to include the other parks within the Sierra Madre mountains for a UNESCO site that would encompass the entire mountain range from Cagayan to Quezon.[2]


Luzon island satellite image showing the range in dark green

In the north, the range starts in the province of Cagayan and ends in the south in the province of Quezon. In the province of Nueva Vizcaya, the Caraballo Mountains lies between Sierra Madre and Cordillera Central.

The mountain range is widely believed to serve as a typhoon barrier for Luzon. However, it is only truly effective for Cagayan Valley where wind exposure and rainfall brought by the typhoon are both reduced. For the rest of Luzon along its western slopes such as in Metro Manila, rainfall is actually enhanced by orographic lifting.[3][4]


The range's highest point is unclear, and several peaks are attributed as the highest. Mount Anacuao in Aurora province stands at 6,069 feet (1,850 m), while Mount Cetaceo in Cagayan is of similar altitude. However, an expedition in September and October 2012 to Mount Guiwan (Nueva Vizcaya) preliminarily measured an altitude of 6,283 feet (1,915 m) on the summit.[5]


List of highest peaks along the mountain range by elevation.

Panorama of the mountains from Mount Oriod
The mountains as viewed near summit of the Mount Oriod in Bulacan


Tinipak or Agos River in Tanay, Rizal

List of major rivers along the mountain range by length.


Daranak Falls in Tanay, Rizal


Two ecoregions cover the Sierra Madre. The Luzon rain forests cover the lower slopes of the range, and are characterized by dipterocarp trees. The Luzon montane rain forests cover the portions of the range above 1000 meters elevation, and are characterized by laurel forests of oak and laurel trees.

National parks

Other protected areas

Signage at Pantabangan–Carranglan Watershed Forest Reserve

Active volcanoes

Indigenous and remote communities

Indigenous peoples

Sierra Madre is home to Indigenous Dumagat-Remontado communities[6] who have ancestral domain claims covering parts of the mountain range.[7][8]

Remote communities

Some coastal communities east of the Sierra Madre mountains, especially from Palanan, Isabela heading north to near the northernmost tip of mainland Cagayan, are remote and isolated with no roads connecting them to towns west of the mountain range. Towns like Palanan, Divilacan and Maconacon, Isabela can only be reached by plane from Cauayan or a boat ride from Aurora province, south of Isabela or from Santa Ana, Cagayan, north of the province. Ilagan City – Divilacan road traversing the Sierra Madre mountain is about to be completed.[9][10]


Lush rainforest in Norzagaray, Bulacan

The Sierra Madre mountain range is rich in genetic, species, and habitat diversity,[11] supplying food, water, and shelter to millions of people.[12] The mountain range hosts multiple watersheds and some of the Philippines' oldest forests.[13] These forests are some of the country's largest remaining forest blocks, including an old-growth dipterocarp forest, montane forests, and extensive lowland forests.[13]

Sierra Madre's forests and watersheds are home to some of the country's richest wildlife communities.[13] More than 291 species of birds and 25 endemic mammals may be found within the Northern Sierra Madre Natural Park alone.[12]

Endemic flora and fauna

Northern Sierra Madre Natural Park, the largest protected area in Sierra Madre range, is home to endemic dipterocarp trees belonging to the Hopea and Shorea genera, orchids such as Dendrobium aclinia, the leguminous tree, Milletia longipes and a member of the citrus family, Swinglea glutinosa as well.[14]

In the forest, in April 2010, the endemic lizard species Northern Sierra Madre Forest monitor lizard – Varanus bitatawa (common name: Butikaw) was described to science, although the Aeta and Ilongot indigenous peoples have known and used it as a food source. The Northern Sierra Madre forest monitor lizard is one of the three frugivorous lizards in the Varanidae family along with V. olivaceus and V. mabitang. All of the three frugivorous lizards are found only in the Philippines.[15]

Endemic mammals in Sierra Madre are the Sierra Madre shrew mouse and Sierra Madre forest mouse.[16]

Non-endemic flora and fauna

Narra, the national tree of the Philippines, Almaciga, and Kamagong can be found on the Sierra Madre range.[17]

Isabela oriole, Philippine eagle, and Philippine crocodile are critically endangered species that can be found in fragmented locations.[17]

Human activities

Lower portions of the Sierra Madre, with habitat damage from logging and charcoal-making.

Forest-loss due to anthropogenic activities

The Sierra Madre mountain range forest habitat is threatened by human activities. Settlers living at the lower portions of the slopes generally are supported by work in logging and charcoal-making. Some portions of the forest cover are already second growth forest. Forest degradation of at least 1,400 hectares per year caused by illegal tree cutting, slash-and-burn farming, fuel-wood collection, illegal hunting, and residential expansion.[17]


A gold and copper mine in the municipality of Kasibu, Nueva Vizcaya, has been operated by the OceanaGold Corporation based in Australia. The Didipio mine is a large-scale open-pit mine in a remote location, and local residents claim the company has severely damaged both the environment for miles around the site, and suppressed the long-standing farming economy.[18] Oceana continues to assert a right to operate despite expiration of its permit, and opposition by organized local residents, the Catholic Church, and worldwide environmental groups.[19]

Hydropower project

The Kaliwa dam project through a project called "New Centennial Water Source" in Sitio Cablao, Brgy. Pagsangahan, General Nakar, Quezon / Sitio Queborosa, Brgy. Magsaysay, Infanta, Quezon is threatening the endangered species living in the sparse remaining forest of Sierra Madre and indigenous people's lives in that area.[20] This project replaced the Kaliwa Low Dam that did not materialize and under the new administration, Rodrigo Duterte approved the Chinese-funded proposal. Aside from the destruction of ecologically important forests, the dam also faces controversy for fulfillment of its financial requirement through a Chinese loan with a 2.0% interest rate rather than a Japanese loan with a 1.25% interest rate.[21][failed verification] The project continues to face strong opposition from the public yet the government is eager to continue.[22] Construction of Kaliwa dam began in 2022.[23]

Conservation efforts

The Mabuwaya Foundation is a non-governmental organization that aims to protect and conserve the Philippine crocodiles and other endemic threatened species. They mainly works in the towns of Divilican and San Mariano in Isabela.[24][25]

On June 19, 2012, in light of the onslaught of Tropical Storm Ondoy on September 26, 2009, Philippine president Benigno Aquino III signed Proclamation No. 413, declaring every September 26 as "Save Sierra Madre Day" in an effort to raise awareness on the benefits that the Sierra Madre brings and the risks and dangers of neglecting it. The proclamation also calls "all sectors of society and the government" to join hands in pursuing activities geared toward the conservation of the Sierra Madre, and to plan, prepare, and conduct activities in observance of Save Sierra Madre Day.[26]


See also


  1. ^ U.S. Coast and Geodetic Survey (1919). "United States Coast Pilot Philippine Islands Part 1", pg. 44. Government Printing Office, Washington.
  2. ^ Coursey, Oscar William (1903). History and Geography of the Philippine Islands. Educator School Supply Company.
  3. ^ Bordadora, Norman (November 12, 2006). "Sierra Madre blocks 'Queenie' punch". Philippine Daily Inquirer. Archived from the original on December 25, 2014. Retrieved December 25, 2014.
  4. ^ Bagtasa, Gerry; Racoma, Bernard Alan (May 31, 2023). "Does the Sierra Madre Mountain Range in Luzon Act as a Barrier to Typhoons?". Philippine Journal of Science. 152 (S1). doi:10.56899/152.S1.05.
  5. ^ Gray, Shirley (2003). The Philippines. Children's Press. ISBN 978-0-516-24212-5.
  6. ^ Noval-Morales, Daisy Y. "The Remontados of the Sierra Madre Mountains". National Commission for Culture and the Arts. Archived from the original on March 4, 2021. Retrieved April 10, 2021.
  7. ^ Chavez, Leilani (November 5, 2019). "A Philippine tribe that defeated a dam prepares to fight its reincarnation". Mongabay Environmental News. Retrieved April 10, 2021.
  8. ^ Valdez, Euden. "Antipolo Dumagats hope new 31,000-tree reforestation project takes root". Philstar. Retrieved April 10, 2021.
  9. ^ Domingo, Leander C. (October 2, 2019). "P1.6-B Isabela road to open soon". The Manila Times. Retrieved April 11, 2021.
  10. ^ Christian (June 13, 2011). "Palanan and Maconacon". Off the Beaten Track in the Philippines. Retrieved on 2014-09-28.
  11. ^ "Northern Sierra Madre Natural Park". DENR-B+WISER.
  12. ^ a b "Northern Sierra Madre Natural Park, the country's biggest natural forest". The Haribon Foundation. August 31, 2016. Retrieved April 9, 2021.
  13. ^ a b c "Forests of Hope site - Mount Irid-Angelo, Philippines". Bird Life International. Retrieved April 9, 2021.
  14. ^ Centre, UNESCO World Heritage. "Northern Sierra Madre Natural Park and outlying areas inclusive of the buffer zone". UNESCO World Heritage Centre.
  15. ^ Welton, L. J.; Siler, C. D.; Bennett, D.; Diesmos, A.; Duya, M. R.; Dugay, R.; Rico, E. L. B.; Van Weerd, M.; Brown, R. M. (2010). "A spectacular new Philippine monitor lizard reveals a hidden biogeographic boundary and a novel flagship species for conservation". Biology Letters. 6 (5): 654–658. doi:10.1098/rsbl.2010.0119. ISSN 1744-9561. PMC 2936141. PMID 20375042.
  16. ^ Heaney, L.R.; Balete, D.S.; Veluz, M.J.; Steppan, S.J.; Esseltyn, J.A.; Pfeiffer, A.W.; Rickart, E.A. (2014). "Two new species of Philippine forest mice (Apomys, Muridae, Rodentia) from Lubang and Luzon Islands, with a redescription of Apomys sacobianus Johnson, 1962". Proceedings of the Biological Society of Washington. 126 (4): 395–413. doi:10.2988/0006-324X-126.4.395. S2CID 49347286.
  17. ^ a b c "Northern Sierra Madre Natural Park". Archived from the original on July 15, 2017. Retrieved January 15, 2022.
  18. ^ "Gold mining policy chaos in Philippines". Asia Times. March 1, 2020.
  19. ^ "Standoff over Philippines' Didipio mines escalates despite COVID-19 lockdown". Mongabay Environmental News. April 6, 2020.
  20. ^ "Kaliwa Dam will destroy Sierra Madre biodiversity – Haribon Foundation". The Haribon Foundation. November 20, 2018.
  21. ^ "Japanese firm renews proposal on Kaliwa Dam project".
  22. ^ "The Philippines' China Dam Controversy".
  23. ^ "Kaliwa Dam construction eyed to start in June". CNN Philippines. February 18, 2022. Archived from the original on June 14, 2022. Retrieved June 17, 2022.
  24. ^ "Mabuwaya - Home".
  25. ^ "Mabuwaya Foundation, Philippines".
  26. ^ Presidential Proclamation No. 413 (June 19, 2012), Declaring September 26 of every year as "Save Sierra Madre Day"