The Alto Paraná Atlantic forests lie to the east, and the Cerrado grasslands to the northeast.

[2] The topography is generally flat or gently rising, and the soils are mostly fine alluvium deposited by the area's rivers.

Grasslands and savannas are generally found on higher ground, and forests along streams and in river floodplains.

The most common trees in the forests are quebracho colorado (Schinopsis balansae) and quebracho blanco (Aspidosperma quebracho-blanco), together with guayacán (Caesalpinia paraguariensis), espina corona (Gleditsia amorphoides), urunday (Myracrodruon balansae), viraró (Ruprechtia laxiflora), palo piedra (Diplokeleba floribunda), guayaibí (Patagonula americana), zapallo caspini (Pisonia zapallo), lapacho negro (Tabebuia ipe), palo borracho del flor rosada (Chorisia speciosa), and itin (Prosopis kuntzei).

[2] Native mammals include puma (Puma concolor), jaguar (Panthera onca), maned wolf (Chrysocyon brachyurus), red brocket (Mazama americana), gray brocket (Mazama gouazoubira), marsh deer (Blastocerus dichotomus), pampas deer (Ozotoceros bezoarticus), White-lipped peccary (Tayassu pecari), collared peccary (Tayassu tajacu), giant anteater (Mymercophaga tridactyla), capybara (Hydrochaerys hydrochaeris), black howler monkey (Alouatta caraya), and Azara’s night monkey (Aotus azarae).