The Pantanal is a tropical wetland and one of the world's largest wetland of any kind. 80% of it lies within the Brazilian state of Mato Grosso do Sul but extends into Mato Grosso as well as into portions of Bolivia and Paraguay, sprawling over an area estimated at between 140,000 square kilometres (54,000 sq mi) and 195,000 square kilometres (75,000 sq mi). Various sub-regional ecosystems exist, each with distinct hydrological, geological and ecological characteristics; up to twelve of them have been defined (RADAMBRASIL 1982).
The name "Pantanal" comes from the Portuguese word pântano, meaning wetland, bog, swamp or marsh. By comparison, the Brazilian highlands are locally referred to as the planalto, plateau or, literally, high plain.