The river was named by the Spanish explorer Francisco de Orellana (1511–1546), who, on his voyage of exploration, said he was attacked by "fierce females" who looked like Amazons of the Greek mythology; however, the existence of a female warrior tribe in that time hasn't been demonstrated and it is possible that they were long-haired Native American warriors who impressed the conqueror, who called the jungle and the river with the name of Amazon.

The following ethnic groups are found in the department: Bora, Cocama, Macuna, Mirana, Okaina, Ticunas, Tucano, Uitoto, Yagua, and Yucuna, among others.

The Amazonas Department covers 109,665 km2 (42,342 sq mi) of protected area, most of it under the name of "forest reserve" since 1959.

There are currently four "National Parks" (Amacayacú, Cahuinarí, Rio Puree, and Yagoje Apaporis).

Amazonas Antioquia Arauca Atlántico Bolívar Boyacá Caldas Caquetá Casanare Cauca Cesar Chocó Córdoba Cundinamarca Guainía Guaviare Huila La Guajira Magdalena Meta Nariño N. Santander Putumayo Quindío Risaralda San Andrés Santander Sucre Tolima Valle del Cauca Vaupés Vichada