Macau [e] or Macao [f] is a special administrative region of the People's Republic of China (PRC). With a population of about 710,000 people [12] and a land area of 32.9 km 2 (12.7 sq mi), it is the most densely populated region in the world.. Formerly a Portuguese colony, the territory of Portuguese Macau was first leased to Portugal by the Ming dynasty as a trading post in 1557.