This extremely rugged, heterogeneous mountainous ecoregion spans the Yukon-Northwest Territories border from Alaska to the Mackenzie Valley. It includes the Ogilvie and Wernecke mountains in its westernmost section, the Backbone Ranges in its interior, and the Canyon Ranges to the east. The eastern ranges of the Mackenzie Mountains that lie in the rain shadow of the higher Selwyn Mountains to the west are also included. The ecoregion shows evidence of localized alpine and valley glaciation. The mean annual temperature for the area is approximately -5°C with a summer mean of 9°C and a winter mean of -19.5°C. Mean annual precipitation is highly variable with the highest amounts, greater than 600 mm, occurring in the southwest portion of the ecoregion. Moving west towards Alaska and the southern Ogilvies, precipitation drops to approximately 400 mm. Higher precipitation occurs at higher elevations. The region is characterized by alpine tundra at upper elevations and subalpine open woodland vegetation at lower elevations. Alpine vegetation consists of lichens, mountain avens, intermediate to dwarf ericaceous shrubs, sedge, and cottongrass in wetter sites. Barren talus slopes are common. Subalpine vegetation consists of discontinuous open stands of stunted white spruce and occasional alpine fir in a matrix of willow, dwarf birch, and Labrador tea. The Ogilvie Mountains, composed of Palaeozoic and Proterozoic sedimentary strata intruded by granitic stocks, reach 2134 m asl in elevation. The Wernecke Mountains are formed of phyllite and nearly horizontal carbonate rocks carved by glaciation. They are divided into several ranges by broad northwesterly-trending valleys. Permafrost is continuous and of low ice content in most of the Yukon portion of the ecoregion. Permafrost is extensive but discontinuous with variable ice content in the Northwest Territories portion of the ecoregion. Alluvium, fluvioglacial deposits, and morainal veneers and blankets are dominant in the region. Rock outcrops are common at higher elevation. Turbic Cryosols with some Dystric Brunisols and Regosols occur on steeply sloping colluvium. Characteristic wildlife includes caribou, grizzly and black bear, Dall's sheep, moose, beaver, fox, wolf, hare, raven, rock and willow ptarmigan, golden eagle, gyrfalcon, and waterfowl. These ranges support various forms of hunting and trapping, and contain considerable mineral potential, but for the most part the ecoregion is an isolated wilderness with little permanent human occupation.
This ecoregion is part of the Taiga Cordillera ecozone.