Geography of the Philippines the Philippines, the Sierra Madre, stretching from Quezon province in the south to Cagayan in the north. 80 percent of the mountain range is tropical rainforest, which is diminishing from rampant illegal logging activity. The range serves as the eastern wall of Luzon Island that protects inhabitants from tropical cyclones usually coming from the Pacific Ocean. The largest plain of the nation is situated in the Central Luzon region and produces most of the national rice supply, earning itself the nickname ""Rice Bowl of the Philippines"". The plains encompass the provinces of Bulacan, Nueva Ecija, Pampanga, Tarlac and Pangasinan. South
Geography of the Philippines The boundaries of the Philippine archipelago are described in Article III of the Treaty of Paris (1898), as comprising an irregular polygon. A box enclosing that polygon would have corners at 20°N 116°E, 20°N 127°E, 4.75°N 127°E, 4.75°N 116°E. The center of this box would lie at 121.5 E, 12.375 N. That point lies roughly in the center of the Tablas Strait between the islands of Tablas and Mindoro. "Republic Act No. 9522", "An Act to Define the Baselines of the Territorial Sea of the Philippines", describes an irregular polygon which fits within a box with its center at 121°44'47.45"E