This reporting unit includes six ecoregions ranging from Mount Logan, (which is 98 per cent perennial snow and ice), to the Yukon Southern Lakes, a region characterized by coniferous forests. Mount Logan, at 5,959 metres, is the highest mountain in Canada, while a half dozen other peaks in the area also exceed 4,000 metres. Several prominent glaciers span a distance of 100 km from their source in Canada to Alaskan tidewater.
Most of the St. Elias Mountains, as well as the Mount Logan ecoregion, are included in the Kluane National Park. The Ruby Range ecoregion consists of rolling to undulating hills, with northern cordilleran boreal forests on the lower slopes and valleys.
Yukon Southern Lakes ecoregion extends from Lake Laberge south to the British Columbia border. Most of the ecoregion lies between 600 and 1,500 m in elevation. The climate is moderated by coastal influences with low precipitation because of the region's location within the rain-shadow of the St. Elias Mountains.
The Yukon Stikine Highlands are composed of three ecoclimates: alpine tundra, subalpine forests and closed forests. This is a transitional zone between the coastal and interior regions and is characterized by subdued mountains and wide valleys.
Wildlife in the southwest is diverse, including grizzly and black bear, caribou, Dall and Stone sheep, mountain goats, moose, deer, beaver, fox, wolf, wolverine, snowshoe hare, marmot, pika, ground squirrel, raven, rock and willow ptarmigan, and golden eagle. Elk and wood bison have also been introduced into the region.