Manus Island is volcanic in origin and probably broke through the ocean's surface in the late Miocene, 8 to 10 million years ago.

Papua New Guinea allowed the government of Australia to run a controversial offshore immigration detention centre, the Manus Regional Processing Centre, which was situated on adjacent Los Negros Island from 2001 to 2017, to house asylum seekers arriving by boat found within Australia's defined territorial borders.

4 Section, 'B' Platoon, 1st Independent Company, Australian Imperial Force,[3] who also provided medical treatment to the inhabitants.

[3] On 8 April 1942 an Imperial Japanese force consisting of the light cruiser Tatsuta, destroyer Mutsuki and a troop transport ship Mishima Maru entered Lorengau harbour and several hundred Japanese soldiers of the 8th Special Base Force swarmed ashore onto the Australian-mandated island.

The ammunition ship USS Mount Hood exploded in Seeadler Harbor on 10 November 1944 with a heavy loss of life of US Navy personnel.

He had already been tried by a British military court in relation to the Sook Ching massacre in Singapore and sentenced to life imprisonment.

Evidence was presented stating that Nishimura had ordered the shootings of wounded Australian and Indian soldiers at Parit Sulong and the disposal of bodies to cover up the killings.

[11] On 26 April 2016, the Supreme Court of Papua New Guinea ruled that the detention of asylum seekers on Manus Island was illegal,[12] and Prime Minister Peter O'Neill announced that the centre would be closed.

[19] The newspaper reported that Australia was countering interest China had placed in expanding Papua New Guinea's port facilities at Wewak, Kikori, Vanimo and Manus Island.