Macau or Macao is a special administrative region of China. It consists of the Macau Peninsula, the islands of Taipa and Coloane, the Cotai reclamation zone between Taipa and Coloane, and several smaller islets. It borders Zhuhai to the north and west, and it lies west of Hong Kong, separated by the Pearl River estuary. With a population of about 720,000 people and a land area of 32.9 square kilometres (12.7 sq mi), it is the most densely populated region in the world.