This ecoregion is a mountainous area of ridges up to 1200m between peaks up to 2500m, located on the southern, Pacific Ocean side of the Alaska Peninsula from Cook Inlet west through the Kodiak Archipelago to Unimak Island at the beginning of the Aleutian Islands chain, while the area around Cook Inlet at the head of the peninsula is the neighboring Cook Inlet taiga ecoregion.

[1] The mountainsides are covered with scrubby vegetation, the higher slopes by low scrub such as black crowberry (Empetrum nigrum) and other ericas (Vaccinium)s, the tiny Arctic willow (Salix arctica) and white mountain avens (Dryas octopetala) while the lower slopes have various evergreen trees among the shrubs and the low coastal plains have tall green alder (Alnus viridis sinuata) and evergreen trees with balsam poplars (Populus balsamifera) in the colder and icyer areas.

Bears found here include the huge Kodiak bear subspecies of brown bear of Kodiak Island and other mammals include caribou (Rangifer tarandus), moose (Alces alces), Arctic ground squirrel (Spermophilus parryii) and Alaskan hare (Lepus othus).

Birds of the area include migrating snow goose and other waterbirds, and breeding colonies of birds such as the tufted puffins, murres and northern fulmars of Unimak Island, Stepovak Bay and the Semidi Islands.

The natural habitat of these mountains is in pristine condition with fishing the main activity of the people.