Papua New Guinea, island country in the southwestern Pacific Ocean. It encompasses the eastern half of New Guinea, the world’s second largest island (the western half is made up of the Indonesian provinces of Papua and West Papua); the Bismarck Archipelago (New Britain, New Ireland, the Admiralty Islands, and several others); Bougainville and Buka (part of the Solomon Islands chain); and small offshore islands and atolls. The national capital, Port Moresby, is located in southeastern New Guinea on the Coral Sea.
The islands that constitute Papua New Guinea were settled over a period of 40,000 years by the mixture of peoples who are generally referred to as Melanesians. Since the country achieved independence in 1975, one of its principal challenges has been the difficulty of governing many hundreds of diverse, once-isolated local societies as a viable single nation.