Brazil’s largest river island, located at the mouth of the Amazon, is Marajó Island.
Marajó lies between the Amazon River and the Tocantins River near the Atlantic coast. With an area of roughly 40,000 square kilometres, it is often described as the world’s largest fluvial island, although the exact ranking depends on how river and coastal islands are classified.
The island contains seasonally flooded grasslands, forests and wetlands. Water buffalo are strongly associated with Marajó and are used in agriculture, transport and local cultural events. The island also gave its name to the Marajoara culture, known for distinctive prehistoric ceramics.
Marajó is sometimes confused with Bananal Island, another enormous Brazilian river island. Bananal is generally described as the world’s largest true river island, while Marajó is influenced by both river and ocean environments. Both are in Brazil.