Palawan (päläˈwän) [key], island (1990 pop. 528,287), 4,550 sq mi (11,785 sq km), 5th largest of the Philippines, N of Borneo and between the Sulu Archipelago and the South China Sea. Lumbering is an important industry on Palawan. There is concern that excessive logging and slash-and-burn farming will deplete the island's rain forests. What little arable land exists on the island is devoted largely to subsistence farming. The island has important mercury and chromite deposits. The population includes many Moros, mostly in the south, and the Batah and the Palawan, mostly in the rain forests. During World War II, it was the site of a Japanese massacre of American prisoners.