Amazonas is a state of Brazil, located in the North Region in the north-western corner of the country. It is the largest Brazilian state by area and the ninth-largest country subdivision in the world. It is the largest country subdivision in South America, being greater than the areas of Chile, Paraguay, and Uruguay combined. Mostly located in the Southern Hemisphere, Amazonas is the third-largest country subdivision in the Southern Hemisphere after the Australian states of Western Australia and Queensland. Located entirely in the Western Hemisphere, it is the fourth-largest country subdivision in the Western Hemisphere after Greenland, Nunavut, and Alaska. If independent, Amazonas could become the sixteenth-largest country in the world, slightly larger than Mongolia. Neighbouring states are Roraima, Pará, Mato Grosso, Rondônia, and Acre. It also borders the nations of Peru, Colombia and Venezuela. This includes the Departments of Amazonas, Vaupés and Guainía in Colombia, as well as the Amazonas state in Venezuela, and the Loreto Region in Peru.

The Amazon River in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile.