[2] The ecoregion occurs along the eastern slope of the Andes from southern Bolivia into northern Argentina, at elevations ranging from 800 to 3,000 metres (2,600 to 9,800 ft).

To the northwest they are bounded by the Bolivian montane dry forests, and by the high-elevation Central Andean puna and High Monte grasslands to the west.

[3] The Southern Andean Yungas consists of a mesic evergreen forest, with trees typically less than 15 metres (49 ft) tall.

[2] Above 2600 meters elevation, the forests transition to subalpine grassland and shrubland (pastizal de neblina),[5] of the Central Andean puna ecoregion.

[2] Mammals that may be found here include the red brocket (Mazama americana), gray brocket (Mazama gouazoupira), white-lipped peccary (Tayassu pecari), collared peccary (Dicotyles tajacu), and South American tapir (Tapirus terrestris).

[5] Characteristic birds of the ecoregion include the Andean condor (Vultur gryphus), barred forest falcon (Micrastur ruficollis), band-tailed pigeon (Patagioenas fasciata), blue-capped puffleg (Eriocnemis glaucopoides), Azara's spinetail (Synallaxis azarae), yellow-striped brushfinch (Atlapetes citrinellus), golden-crowned warbler (Basileuterus culicivorus), two-banded warbler (Myiothlypis bivittata), and Andean slaty thrush (Turdus nigriceps).

[5] Birds endemic to this ecoregion include the red-faced guan (Penelope dabbenei), Tucumán amazon (Amazona tucumana), Rothschild's swift (Cypseloides rothschildi), and the rufous-throated dipper (Cinclus schulzi).

[6] The critically endangered frog Telmatobius ceiorum is endemic to the Yungas of the Sierra del Aconquija.