Bougainville Island is the main island of the Autonomous Region of Bougainville of Papua New Guinea

Papua New Guinea

Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...

. This region is also known as Bougainville Province or the North Solomons. The population of the province is 175,160 (2000 census), which includes the adjacent island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

 of Buka

Buka Island

Buka Island is the second largest island in the Papua New Guinean province of Bougainville.- History :Buka was first occupied by humans in paleolithic times, some 30,000 years ago...

 and assorted outlying islands including the Carterets

Carteret Islands

The Carteret Islands are Papua New Guinea islands located 86 km  north-east of Bougainville in the South Pacific...

. Although Bougainville Island is geographically part of the Solomon Islands archipelago

Solomon Islands (archipelago)

The Solomon Islands are an archipelago in the South-Western Pacific Ocean, northeast of Australia, in the region known as Melanesia. The archipelago is currently divided between two countries; Papua New Guinea, in which they make up the autonomous province of Bougainville; and the Solomon Islands,...

, the nation of the Solomon Islands

Solomon Islands

Solomon Islands is a sovereign state in Oceania, east of Papua New Guinea, consisting of nearly one thousand islands. It covers a land mass of . The capital, Honiara, is located on the island of Guadalcanal...

 is a separate state.
The first human settlement of Bougainville occurred some 28,000 years ago from New Ireland

New Ireland (island)

New Ireland is a large island in Papua New Guinea, approximately 7,404 km² in area. It is the largest island of the New Ireland Province, lying northeast of the island of New Britain. Both islands are part of the Bismarck Archipelago, named after Otto von Bismarck, and they are separated by...

.