The moist forests cover an area of 216,100 square kilometres (83,400 sq mi), encompassing a region of mountains and plateaus in the Brazilian states of São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul, and extending into Misiones Province of Argentina.

[citation needed] The ecoregion is bounded by the Alto Paraná Atlantic forests to the north, west, and south, the Cerrado savannas and shrublands to the northeast, The Serra do Mar coastal forests to the east, and the Uruguayan savanna to the southwest.

[citation needed] The Araucaria moist forests have an oceanic temperate climate (Cfb), with frequent frosts during the winter months and considerable snowfalls (generally light) in the highest areas.

[citation needed] The ecoregion mostly consists of evergreen subtropical moist forests, with a canopy made up of the broadleaved trees Ocotea pretiosa, O. catharinense, and O. porosa (Lauraceae), Campomanesia xanthocarpa (Myrtaceae), and Mimosa scabrella and Parapiptadenia rigida (both Leguminosae).

[citation needed] The ecoregion is home to several threatened species endemic to the Atlantic forests, including the brown howler monkey (Alouatta guariba) and the red-spectacled parrot (Amazona pretrei).