The third-largest island in the world by area is Borneo, located in Southeast Asia and shared by three nations: Indonesia, Malaysia, and Brunei. This vast island is renowned for its rich biodiversity, ancient rainforests, and diverse cultural heritage.
Borneo is surpassed in size only by Greenland and New Guinea, making it a significant landmass in terms of both geography and ecological importance.
Geography of Borneo
With an area of approximately 748,168 square kilometers (288,869 square miles), Borneo is located in the Malay Archipelago, a vast collection of islands in Southeast Asia that includes some of the world’s most famous tropical destinations.
The island lies to the north of Java and to the west of Sulawesi, bordered by the South China Sea to the northwest, the Sulu Sea to the northeast, the Celebes Sea to the east, and the Java Sea to the south.
Unique geographical features of Borneo
Borneo is a land of striking geographical diversity, with its dense rainforests, towering mountains, sprawling caves, and meandering rivers.
Mount Kinabalu
As the highest peak in Borneo, Mount Kinabalu reaches an impressive 4,095 meters (13,435 feet) and dominates the skyline of Malaysia’s Sabah state.
This towering mountain is not only a popular destination for hikers but is also recognized as a UNESCO world heritage site due to its unique ecosystems and rich plant biodiversity. It supports over 5,000 plant species, including many species of orchids and the rare Rafflesia, the largest flower in the world.
Kinabatangan River
The Kinabatangan River, located in Sabah, is Malaysia’s second-longest river and one of the most biodiverse ecosystems on the island. This winding river flows through dense jungles, providing a habitat for endangered species like the Bornean orangutan, pygmy elephant, and proboscis monkey.
Boat tours along the Kinabatangan allow visitors to experience one of Borneo’s most vibrant wildlife regions up close.
The Caves of Sarawak
Sarawak, in Malaysian Borneo, is known for its incredible limestone cave systems. Among the most famous is the Mulu Caves, part of the Gunung Mulu National Park, another UNESCO world heritage site. Within this cave system, the Sarawak Chamber holds the title of the world’s largest cave chamber by area.
The park is also home to Deer Cave, which contains a massive colony of bats that famously emerge in the evening in a mesmerizing, swirling display against the sky.
Rainforests and peat swamps
Borneo’s rainforests are among the oldest and most biologically diverse in the world, dating back over 130 million years.
The island also has extensive peat swamp forests, which play a critical role in carbon storage, helping to mitigate climate change. The forests support an incredible variety of flora and fauna, including some of the rarest species on the planet.
Natural phenomena in Borneo
Borneo’s unique location and varied ecosystems give rise to natural phenomena that are both scientifically significant and awe-inspiring.
Tropical rainfall and monsoon patterns
The third-largest island in the world by area experiences a humid, tropical climate with consistent rainfall throughout the year. Monsoon winds bring heavy rains, especially from November to March, resulting in lush vegetation and high levels of biodiversity.
These rains are crucial for sustaining the dense rainforests and river systems that support countless species. However, they can also lead to seasonal flooding, particularly in low-lying regions.
Firefly synchronization
In certain parts of Borneo, particularly along the Kinabatangan River, fireflies put on a natural light show that captivates visitors.
These fireflies synchronize their flashing patterns in perfect unison, lighting up the riverbanks at dusk in a mesmerizing display. This phenomenon is rare, as fireflies in most regions flash at random intervals rather than in sync.
Equatorial climate
Borneo’s location near the equator means it has minimal seasonal temperature changes. This steady climate supports the lush tropical rainforests that the island is known for.
However, being near the equator also makes Borneo more vulnerable to the impacts of climate change, which can disrupt the delicate balance of its ecosystems and threaten native species.
Rare species
Borneo is home to several endemic species of animals and plants that are found nowhere else on Earth. These include the endangered Bornean orangutan, the Bornean pygmy elephant, the Sumatran rhinoceros, the Bornean clouded leopard, and the carnivorous Asia pitcher plant.
The island’s isolation and unique climate have enabled these species to evolve separately from their mainland relatives, making them incredibly specialized for their environment.
Cultural celebrations rooted in nature
Indigenous communities in Borneo, such as the Dayak people, hold deep cultural connections with the land.
Many of their festivals celebrate the natural rhythms of the island, such as the Gawai Dayak festival in Sarawak, which marks the end of the rice harvest season. These celebrations showcase the interdependence between Borneo’s people and its unique natural environment.
The unique division of Borneo among three nations
One of the most fascinating aspects of Borneo is its division among three countries — a rarity among islands worldwide. The island is politically divided into three territories:
- Indonesia’s Kalimantan: This southern region constitutes around 73% of Borneo’s total area. As the largest section of the island, Kalimantan is characterized by its sprawling rainforests, remote villages, and vast river systems, which play an essential role in local transportation and trade.
- Malaysian Borneo: In the north, Malaysian Borneo is comprised of two states: Sabah and Sarawak. Sabah is known for its rugged landscapes, including Mount Kinabalu, Borneo’s highest peak and one of Southeast Asia’s tallest mountains. Sarawak is famous for its extensive cave systems and intricate river networks.
- Brunei: This small, oil-rich nation occupies a relatively tiny portion of Borneo, nestled between Sabah and Sarawak. Despite its small size, Brunei boasts lush forests and a rich cultural heritage that distinguishes it from its neighbors.
This political division adds a fascinating cultural dimension to Borneo, as each region has its own distinct identity shaped by the nation it belongs to. Kalimantan, for instance, showcases Indonesian influences, while Sabah and Sarawak reflect Malaysian heritage, and Brunei maintains its traditional monarchy and culture.
Map of the third-largest island in the world by area
To explore a detailed map of the world’s third-largest island by area, click the image below to open it in Google Maps. Once there, tap the ‘star’ icon to add it to your maps for easy access later.
