It occupies a narrow coastal zone of Alaska, between the Pacific Ocean and the northernmost Pacific Coast Ranges, covering an area of 23,300 square miles (60,400 square kilometers), extending from the Alexander Archipelago in southeast Alaska along the Gulf of Alaska to the western Kenai Peninsula and eastern Kodiak Island.

The ecoregion receives high rainfall, which varies considerably based on exposure and elevation.

Conifers are the characteristic trees, and the predominant species are Sitka spruce (Picea sitchensis), western hemlock (Tsuga heterophylla), and mountain hemlock (Tsuga mertensiana), together with shore pine (Pinus contorta), western red cedar (Thuja plicata), and yellow cedar (Callitropsis nootkatensis).

Sites with poor drainage and along river channels are home to broadleaf trees, including alder (Alnus spp.

), black cottonwood (Populus trichocarpa), and paper birch (Betula papyrifera).