Bougainville, officially the Autonomous Region of Bougainville, is an autonomous region in Papua New Guinea. The largest island is Bougainville Island, while the region also includes Buka Island and a number of outlying islands and atolls. The current capital is Buka, situated on Buka Island.
In 2011, the region had an estimated population of 250,000. The lingua franca of Bougainville is Tok Pisin, while a variety of Austronesian and non-Austronesian languages are also spoken. The region includes several Polynesian outliers where Polynesian languages are spoken.
Wikipedia https://en.wikipedia.org/wiki/Autonomous_Region_of_Bougainville
Coordinates -5°25'56.706" N 154°40'12.661" E