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 km2 (178,700 mi2) includes a large mainland and hundreds of islands.
The eastern half of New Guinea was divided in 1884 between German New Guinea in the north and British New Guinea in the south, with the latter ceded to Australia in 1902 and reorganised as the Territory of Papua. Australia occupied German New Guinea during World War I and then administered the territory as a League of Nations mandate. 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 was granted independence as a Commonwealth realm in 1975. Representing the monarch is a Governor-General. Politics take place within a Westminster system, with the government led by a prime minister. Members of the National Parliament, the unicameral legislative body, also serve as provincial leaders.
The population is highly rural, with only 14% living in urban centres in 2023. The persistence of traditional communities and lifestyles are explicitly protected by the Papua New Guinea Constitution. While official population estimates suggest the population is around 11.8 million, estimates using satellite data put the number closer to 17 million. The population is extremely diverse. There are 840 known spoken languages, making it the most linguistically diverse country in the world. Cultural practices are similarly diverse. Many cultural and linguistic groups are small, although English and Tok Pisin serve as common languages. This diversity has led to friction, especially in politics, and the government has struggled to combat violence against women.
The country has a large Christian majority population, of several different denominations, and in March 2025 its constitution was amended to adopt Christianity as the official state religion.
The rural and diverse population is a result of highly mountainous geography. The land supports around 5% of all known species, and the export-driven economy is also dependent on natural resources. Papua New Guinea is a developing economy where nearly 40% of the population are subsistence farmers living relatively independently of the cash economy. The country retains close ties to Australia, and has enhanced ties with both Asia and the Pacific.
"Papua" is derived from a local term of uncertain origin, that may have referred to at least part of the island now called New Guinea. In 1526 Portuguese explorer Jorge de Menezes named the island Ilhas dos Papuas. The Australian government adopted the name "Territory of Papua" when it assumed control of British New Guinea in 1902, which Prime Minister Edmund Barton considered a "shorter and better name" for the territory.
"New Guinea" (Nueva Guinea) was the name coined by the Spanish explorer Yñigo Ortiz de Retez. In 1545, he noted the resemblance of the people to those he had earlier seen along the Guinea coast of Africa. Guinea, in its turn, is etymologically derived from the Portuguese word Guiné. The name is one of several toponyms sharing similar etymologies, which likely mean "of the burnt face" or similar, in reference to the dark skin of the inhabitants. Its use in the country name comes from the Territory of New Guinea, the name adopted for German New Guinea when it became a League of Nations mandate under Australian administration.
The hyphenated form "Papua-New Guinea" was adopted by the Papua‑New Guinea Provisional Administration Act 1945, after previous use to refer to the two Australian-administered territories. The name "Territory of Papua and New Guinea" was used following formal administrative union in 1949. Beginning in the 1960s, there was considerable debate around whether the territory should adopt a new name upon independence. The indigenised name "Niugini" won a 1968 competition held by the South Pacific Post and was adopted by several nationalist groups, while "Pagini" was favoured by a parliamentary committee into constitutional development. In 1971, the House of Assembly renamed the territory "Papua New Guinea", which was retained upon independence.
Archaeological evidence indicates that modern humans first arrived in what became New Guinea and Australia, as well as the Bismarck Archipelago, around 42,000 to 45,000 years ago. Bougainville was settled by around 28,000 years ago, and the more distant Manus Island by around 20,000 years ago. These were part of the earliest migrations of humans from Africa, and the resulting populations remained relatively isolated from the rest of the world throughout prehistory. Rising sea levels isolated New Guinea from Australia about 10,000 years ago, although Aboriginal Australians and New Guineans had already diverged from each other from about 37,000 years ago.
Agriculture was independently developed in the New Guinea highlands around 7000 BC, making it one of the few areas in the world where people independently domesticated plants. Before the onset of full-scale agriculture, some plants had already been domesticated, including sago, Canarium indicum, and karuka. Archaeological evidence shows that Austronesian-speaking peoples of the Lapita culture reached the Bismarck Archipelago by 3,300 years ago. It is unknown whether they also settled on the mainland at this time, but there is strong evidence of their presence in coastal areas from around 500 BC. These communities interacted with larger trade networks. It is likely through these trading networks that banana and sugarcane moved from New Guinea to other areas of the world.
Trade became rarer around 300 AD, as demand for goods shifted to the Maluku Islands and Timor. After European interest in the region grew in the 16th century, Dutch influence grew over the Sultanate of Tidore. As Dutch authorities become more interested in New Guinea, they confirmed and extended the sultanate's claims over western New Guinea. Renewed trade began to spread to the eastern parts of New Guinea in the late 17th century, driven by demand for goods such as dammar gum, sea cucumbers, pearls, copra, shells, and bird-of-paradise feathers.
On New Guinea, communities were economically linked through trading networks. Despite this, aside from some political alliances, each community functioned largely independently, relying on subsistence agriculture. Goods were often traded along established chains, and some villagers would be familiar with and sometimes know the languages of the immediately neighbouring villages (although language by itself was not a marker of political allegiance). Some wider trading networks existed in maritime areas. While people did not move far along these routes, goods moved long distances through local exchanges, and cultural practices likely diffused along them. Despite these links, the creation of larger political entities under European rule had no precedent, and in many cases brought together communities that historically had antagonistic relationships, or no relationship at all.
It is likely that some ships from China and Southeast Asia visited the island at times, and that there was some contact with New Guinean communities. The Portuguese explorer António de Abreu was the first European to discover the island of New Guinea. Portuguese traders introduced the South American sweet potato to the Moluccas. From there, it likely spread into what is today Papua New Guinea sometime in the 17th or 18th century, initially from the southern coast. It soon spread inland to the highlands, and became a staple food. The introduction of the sweet potato, possibly alongside other agricultural changes, transformed traditional agriculture and societies. This likely led to the spread of the Big man social structure. Sweet potato largely supplanted the previous staple, taro, and led to significant population growth in the highlands.