The Bismarck Archipelago is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea. Its area is about 50,000 square km.

The largest islands are New Britain and New Ireland. New Ireland is approximately 7,404 km2 (2,859 sq mi) in area. It is the largest island of New Ireland Province, lying northeast of the island of New Britain. New Britain (Tok Pisin: Niu Briten) is the largest island in the Bismarck Archipelago and Papua New Guinea. It is crescent-shaped, approximately 520 km (320 mi) along its southeastern coastline, and from 29 to 146 km (18–91 miles) wide, not including a small central peninsula.

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