Taiwan, officially the Republic of China (ROC), is an island country located in East Asia. The main island of Taiwan, formerly known in the West as Formosa, makes up 99% of the land area of the territories under ROC control. The main island measures 35,808 square kilometres (13,826 sq mi) and lies some 180 kilometres (112 mi) across the Taiwan Strait from the southeastern coast of the People's Republic of China (PRC). The East China Sea lies to the north of the island, the Philippine Sea to its east, the Luzon Strait directly to its south and the South China Sea to its southwest. The ROC also controls a number of smaller islands, including the Penghu archipelago in the Taiwan Strait, the Kinmen and Matsu Islands near the PRC's coast, and some of the South China Sea Islands.