This is a band of mountain habitat running north–south along the leeward side of the Cascade Mountains in British Columbia, Canada and Washington, United States, with the Okanagan Highland to the south on the US-Canada border and the Chilcotin Ranges to the north.

[2] This is a varied mountain landscape of rugged, snowy peaks, glaciers and alpine meadows.

Higher elevation subalpine slopes are home to Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa) and lodgepole pine (Pinus contorta) while lower montane forests consist of lodgepole pine, quaking aspen (Populus tremuloides), white spruce (Picea glauca) and Rocky Mountain Douglas-fir.

Wildlife of the mountains includes bighorn sheep (Ovis canadensis), mountain goat (Oreamnos americanus), grizzly bear (Ursus arctos) and black bear (Ursus americanus), black-tailed deer (Odocoileus hemionus), coyote (Canis latrans) and cougar (Puma concolor couguar)[2] with smaller mammals such as the northern flying squirrel.

The Fraser River is particularly important for salmon and also acts as a barrier to the movement of wildlife within the region.