This ecoregion includes the Mistassini Hills at the western limit of the boreal coniferous forest in west-central Quebec. It is marked by cool summers and cold winters. Summers are warmer in the southern part of the ecoregion below Lac Mistassini. The mean annual temperature is approximately 0°C. The mean summer temperature is 12.5°C and the mean winter temperature is -13.5°C. The mean annual precipitation ranges 650-900 mm. This ecoregion is classified as having a mid- to high boreal ecoclimate. The Chibougamau Hills occur southwest of Lac Mistassini in west-central Quebec. They are underlain by massive, crystalline, Archean granites, acidic intrusives, and volcanic rocks. The ecoregion's broad, rolling surfaces lie 300-350 m asl and are covered with thin, discontinuous veneers of glacial drift intermixed with organic deposits in depressions. Numerous fluvioglacial complexes fill the valleys. Productive, closed stands of black spruce and balsam fir are dominant in the region. Fires perpetuate black spruce, even though balsam fir is the climatic climax species. Open stands of white spruce with lichen and paper birch occur occasionally on well-drained sites. Feathermoss is a common ground cover, whereas sphagnum occurs in poorly drained depressions. The Mistassini Hills consist of subparallel hills, ridges, and valleys. The valleys are partially filled with the waters of Lac Mistassini. Summits are usually more than 1065 m asl in elevation in the Otish Mountains and stand 760 m above the lake. Most of the ridges are north-facing cuestas formed of Archean sedimentary rocks and gabbro sills that have a generally subdued aspect around the lake. The region is underlain by Precambrian granites and gneisses, has an undulating drift-covered surface, and is generally lower than adjoining uplands to the east. Surficial deposits are predominantly thin, discontinuous veneers of sandy and stony till. Humo-Ferric Podzols are the dominant soils, whereas Mesisols and Fibrisols are common in peat-filled depressions. Characteristic wildlife species include caribou, black bear, wolf, moose, lynx, and snowshoe hare. Bird species include Canada goose, ruffed grouse, and American black duck. Forestry, mining, hunting, and trapping, as well as outdoor recreation, are the principal land use activities. The main community is Chibougamau. The population of the ecoregion is approximately 13 600.
This ecoregion is part of the Boreal Shield ecozone.