an island in the Philippines. Area, 9,800 sq km. It has a mountainous terrain, and the highest massifs are Mount Halcon (2,582 m) in the northwest and Mount Baco (2,488 m) in the central part. The mountains are composed of granite, diorite, schist, and sedimentary rock. A hilly plain extends along the coast.
The climate is subequatorial and monsoonal. In the east rainfall is even throughout the year, but in the west there is a dry season in winter and spring. Damp tropical and monsoonal forests are found on the slopes, and mangrove forests grow in places along the coast. The coastal plain is tilled (rice, sugarcane, and coconut palms). Fishing and gold mining are also important. The principal cities are Calapan and Mamburao.