RADAR TULUNGAGUNG – The division of Papua between Indonesia and Papua New Guinea remains one of the most complex colonial legacies in Southeast Asia and the Pacific. Although the island shares the same landmass, European powers created a border more than a century ago that still separates the region into two nations today.

Indonesia gained control of the western half of the island after years of diplomatic disputes and military confrontation with the Netherlands. At the same time, Britain, Germany, and later Australia governed the eastern side before Papua New Guinea achieved independence in 1975.

The history behind Papua’s division stretches from colonial expansion in the 19th century to Cold War negotiations and the controversial Act of Free Choice in 1969. Those events shaped modern borders in the region and continue to influence political tensions and separatist movements in Papua today.

Colonial Powers Drew the Border Across Papua

Before European colonization, the island of New Guinea was inhabited by hundreds of indigenous Papuan tribes spread across mountainous regions, dense rainforests, and coastal settlements. Communities relied heavily on nature and local traditions, with no centralized kingdom or unified political system controlling the island.

European interest in the island intensified during the Age of Exploration. Spanish explorers in the 16th century named the island “Nueva Guinea” because they believed the indigenous inhabitants resembled people from Guinea in Africa. However, Spain never established major colonial control over the territory.

The island later became strategically important for European powers competing in the Asia-Pacific region. By the 19th century, the Dutch had consolidated control over much of the Indonesian archipelago and began establishing administrative posts in western Papua.

In 1895, the Netherlands and Britain formalized territorial boundaries through agreements that divided the island into separate colonial administrations. The western half fell under Dutch authority, while the eastern territories were controlled by Britain and Germany before eventually coming under Australian administration.

That colonial-era division ultimately shaped the modern borders separating Indonesia and Papua New Guinea today.

Indonesia and the Netherlands Clashed Over West Papua

After Japan’s defeat in World War II, Indonesia declared independence on August 17, 1945. Indonesian nationalists argued that all former territories of the Dutch East Indies, including West Papua, should automatically become part of the newly independent republic.

The Netherlands, however, refused to transfer control of West Papua. Dutch authorities claimed the Papuan population had distinct ethnic and cultural characteristics compared with other regions in Indonesia and argued the territory should prepare for separate self-determination.

The dispute intensified after the 1949 Round Table Conference, known in Indonesia as KMB, when the Netherlands officially recognized Indonesian sovereignty but excluded West Papua from the agreement.

Indonesia’s first president, Sukarno, strongly rejected the Dutch position. He insisted that West Papua remained an inseparable part of the former Dutch East Indies and therefore belonged to Indonesia. Diplomatic tensions escalated throughout the 1950s and early 1960s.

In 1961, Indonesia launched Operation Trikora, a military and political campaign aimed at ending Dutch control in West Papua. The confrontation raised international concern during the Cold War period, particularly as both Western and Soviet blocs monitored developments closely.

The New York Agreement and Papua’s Integration Into Indonesia

International pressure eventually pushed both sides toward negotiations under the United Nations.

In August 1962, Indonesia and the Netherlands signed the New York Agreement, which transferred temporary administration of West Papua to the United Nations Temporary Executive Authority (UNTEA). The UN officially assumed control on October 1, 1962, before transferring the territory to Indonesia in 1963.

One major condition of the agreement required Indonesia to organize a referendum allowing Papuans to determine their political future.

The process, known as the Act of Free Choice or Pepera, took place in 1969 under UN supervision. Instead of a one-person-one-vote system, Indonesia selected 1,026 representatives who unanimously voted to remain part of Indonesia.

The United Nations later acknowledged the results, although the process has remained controversial among Papuan independence groups and international observers for decades.

Following integration, the territory was renamed several times, including Irian Barat and later Irian Jaya, before officially becoming Papua in 2000 following local demands for cultural recognition.

Separatist Conflict and Papua New Guinea’s Different Path

Despite becoming part of Indonesia, separatist resistance continued through the Free Papua Movement, widely known as OPM. Low-intensity conflict and political tensions have persisted in several regions of Papua for decades, fueled by demands for independence, allegations of human rights abuses, and disputes over economic inequality.

Meanwhile, the eastern half of the island followed an entirely different colonial path. Papua New Guinea was never part of the Dutch East Indies. Instead, it was administered successively by Britain, Germany, and Australia.

Papua New Guinea eventually gained independence from Australia in 1975, which explains why it did not become part of Indonesia after Indonesian independence in 1945.

Today, the island of New Guinea remains geographically united but politically divided between two sovereign states, with a border rooted in colonial decisions made more than a century ago.