large, tropical rainforest occupying the drainage basin of the Amazon River and its tributaries in northern South America, and covering an area of 2,300,000 square miles (6,000,000 square km). Comprising about 40 percent of Brazil's total area, it is bounded by the Guiana Highlands to the north, the Andes Mountain Ranges to the west, the Brazilian central plateau to the south, and the Atlantic Ocean to the east.

Amazonia is the largest river basin in the world, and its forest stretches from the Atlantic Ocean in the east to the tree line of the Andes in the west. The forest widens from a 200-mile (320-km) front along the Atlantic to a belt 1,200 miles (1,900 km) wide where the lowlands meet the Andean foothills. The immense extent and great continuity of this rainforest is a reflection of the high rainfall, high humidity, and monotonously high temperatures that prevail in the region.

The Amazon Rainforest is the world's richest and most varied biological reservoir, containing several million species of insects, plants, birds, and other forms of life, many still unrecorded by science. The luxuriant vegetation encompasses a wide variety of trees, including many species of myrtle, laurel, palm, and acacia, as well as rosewood, Brazil nut, and rubber tree. Excellent timber is furnished by the mahogany and the Amazonian cedar. Major wildlife includes jaguar, manatee, tapir, red deer, capybara and many other types of rodents, and several types of monkeys.

In the 20th century, Brazil's rapidly growing population settled major areas of the Amazon Rainforest. The Amazon forest shrank dramatically as a result of settlers' clearance of the land to obtain lumber and to create grazing pastures and farmland. In the 1990s the Brazilian government and various international bodies began efforts to protect parts of the forest from human encroachment, exploitation, and destruction.