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.

The first inhabitants of the archipelago arrived around 33,000 years ago from New Guinea, either by boats across the Bismarck Sea or via a temporary land bridge, created by an uplift in the Earth's crust. Later arrivals included the Lapita people.

The first European to visit these islands was Dutch explorer Willem Schouten in 1616. The islands remained unsettled by western Europeans until they were annexed as part of the German protectorate of German New Guinea in 1884. The area was named in honour of the Chancellor Otto von Bismarck.

On 13 March 1888, a volcano erupted on Ritter Island causing a megatsunami. Almost 100% of the volcano fell in to the ocean leaving a small crater lake.

Following the outbreak of World War I, the Australian Naval and Military Expeditionary Force seized the islands in 1914 and Australia later received a League of Nations mandate for the islands. They remained under Australian administration — interrupted only by Japanese occupation during World War II — until Papua New Guinea became independent in 1975.