The
Sierra Madre Mountains is the longest mountain range in the
Philippines. Running in the north-south direction from the provinces of
Cagayan to the north and
Quezon to the south, the mountains form the eastern backbone of
Luzon Island, the largest island of the
archipelago. It is bordered by the
Pacific Ocean to the east. The Pacific coast of Luzon along the Sierra Madre is less developed as the lofty and continuous mountains forms a bold and an almost inaccessible shore, exposed to the full force of the northeast monsoon and the waves of the Pacific Ocean. Some of communities east of the mountain range and along the coast are so remote they are still only accessible by plane or by boat.