This is a list of freshwater ecoregions in Latin America and the Caribbean, as identified by the World Wildlife Fund (WWF). The WWF divides the Earth's land surface into ecoregions, defined as "large area[s] of land or water containing a distinct assemblage of natural communities and species". Ecoregions are grouped into complexes and bioregions, defined as, "a complex of ecoregions that share a similar biogeographic history, and thus often have strong affinities at higher taxonomic levels (e.g. genera, families)." The Earth's land surface is divided into eight biogeographic realms. Latin America corresponds, roughly, to the Neotropical realm, although northern Mexico lies within the Nearctic.