Territory of Papua in the context of South West Pacific Area

Papua New Guinea (PNG), officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean north of Australia. It has a land border with Indonesia to the west and maritime borders with Australia to the south and the Solomon Islands to the east. Its capital is Port Moresby. The country's 462,840 km (178,700 sq mi) includes a large mainland and hundreds of islands. The majority of the country's land is held under the collective customary ownership of local clans. This protected tenure is globally exceptional due to remarkable legislative protections granted in PNG’s national constitution.

The territory of Papua New Guinea was split in the 1880s between German New Guinea in the north and the British Territory of Papua in the south, the latter of which was ceded to Australia in 1902. All of present-day Papua New Guinea came under Australian control following World War I, although it remained two distinct territories. The nation was the site of fierce fighting during the New Guinea campaign of World War II, following which the two territories were united in 1949. Papua New Guinea became an independent Commonwealth realm in 1975. Representing the King is a Governor-General. Politics takes place within a Westminster system, with the government led by a Prime Minister. Members of the national parliament also serve as provincial leaders.

The New Guinea campaign of the Pacific War lasted from January 1942 until the end of the war in August 1945. During the initial phase in early 1942, the Empire of Japan invaded the Territory of New Guinea on 23 January and Territory of Papua on 21 July and overran western New Guinea (part of the Netherlands East Indies) beginning on 29 March. During the second phase, lasting from late 1942 until the Japanese surrender, the Allies—consisting primarily of Australian forces—cleared the Japanese first from Papua, then New Guinea, and finally from the Dutch colony.

The campaign resulted in a crushing defeat and heavy losses for the Empire of Japan. As in most Pacific War campaigns, disease and starvation claimed more Japanese lives than enemy action. Most Japanese troops never even came into contact with Allied forces and were instead simply cut off and subjected to an effective blockade by Allied naval forces. Garrisons were effectively besieged and denied shipments of food and medical supplies, and as a result, some researchers claim that 97% of Japanese deaths in this campaign were from non-combat causes. According to John Laffin, the campaign "was arguably the most arduous fought by any Allied troops during World War II."

South West Pacific Area (SWPA) was the name given to the Allied supreme military command in the South West Pacific Theatre of World War II. It was one of four major Allied commands in the Pacific War. SWPA included the Philippines, Borneo, the Dutch East Indies (excluding Sumatra), East Timor, Australia, the Territories of Papua and New Guinea, and the western part of the Solomon Islands. It primarily consisted of United States and Australian forces, although Dutch, Filipino, British, and other Allied forces also served in the SWPA.

The Colony of Queensland was a colony of the British Empire from 1859 to 1901, when it became a State in the federal Commonwealth of Australia on 1 January 1901. At its greatest extent, the colony included the present-day State of Queensland, the Territory of Papua and the Coral Sea Islands Territory.

The Territory of New Guinea was an Australian-administered territory, first as a League of Nations mandate and then as a United Nations trust territory, in the northeastern part of the island of New Guinea and nearby islands, from 1914 until 1975. In 1949, it was united with the Territory of Papua to create the Territory of Papua and New Guinea. That administrative union was renamed as Papua New Guinea in 1971. Notwithstanding that it was part of an administrative union, the Territory of New Guinea at all times retained a distinct legal status and identity until the advent of the Independent State of Papua New Guinea.

The initial Australian mandate, entitled the Mandate for the German Possessions in the Pacific Ocean situated South of the Equator other than German Samoa and Nauru, was based on the previous German New Guinea, which had been captured and occupied by Australian forces during World War I.

The Territory of Papua and New Guinea was established by an administrative union between the Australian-administered territories of Papua and New Guinea (the latter being a United Nations trust territory administered by Australia) in 1949. In December 1971, the name of the Territory changed to "Papua New Guinea" and in 1975 it became the Independent State of Papua New Guinea.

Papua New Guinea (PNG), officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean north of Australia. It has a land border with Indonesia to the west and maritime borders with Australia to the south and the Solomon Islands to the east. Its capital is Port Moresby. The country's 462,840 km (178,700 sq mi) includes a large mainland and hundreds of islands.

The territory of Papua New Guinea was split in the 1880s between German New Guinea in the north and the British Territory of Papua in the south, the latter of which was ceded to Australia in 1902. All of present-day Papua New Guinea came under Australian control following World War I, although it remained two distinct territories. The nation was the site of fierce fighting during the New Guinea campaign of World War II, following which the two territories were united in 1949. Papua New Guinea became an independent Commonwealth realm in 1975. Representing the King is a Governor-General. Politics takes place within a Westminster system, with the government led by a Prime Minister. Members of the national parliament also serve as provincial leaders.

The New Guinea Act 1920 was an act passed by the Parliament of the Commonwealth of Australia, which saw the transfer of the territory of German New Guinea from Germany to Australia under terms of the Treaty of Versailles.

The act formally established the Territory of New Guinea as a League of Nations Mandated Territory that was to be administered by Australia. The act remained in effect until New Guinea's merger with the Territory of Papua following the passage of the Papua and New Guinea Act 1949.