This ecoregion lies between Sault Ste. Marie and the Ottawa River valley in southern Ontario. The ecoregion is marked by warm summers and cold winters. The mean annual temperature is approximately 3.5°C. The mean summer temperature is 15.5°C and the mean winter temperature is -8.5°C. The mean annual precipitation ranges 900-1000 mm. Mean annual precipitation exceeds 1000 mm near Georgian Bay. This ecoregion is classified as having a humid high cool temperate ecoclimate. The dominant vegetation is mixedwood forest of sugar maple, yellow birch, eastern hemlock, and eastern white pine with beech appearing on warmer sites. Dry sites are dominated by red and eastern white pine, and red oak. Wetter sites support red maple, black ash, white spruce, tamarack, and eastern white cedar. The ecoregion is underlain by massive, crystalline, acidic, Archean bedrock that forms broad, sloping uplands and lowlands. Strongly glaciated, it is characterized by ridged to hummocky rock outcrops covered with discontinuous acidic morainal tills, and significant areas of coarse, fluvioglacial, and lacustrine deposits. Exposed bedrock is common, particularly north and west of Lake Nipissing. Humo-Ferric Podzols are the dominant soil, and significant inclusions are Gray Luvisols on finer-grained lacustrine sediments near Espanola and Parry Sound, and Gleysolic soils near Lake Nipissing and Sudbury. Wetlands in the ecoregion are concentrated between Lake Nipissing and Georgian Bay. They are characterized by bowl bogs that are treed and frequently surrounded by peat margin swamps. Characteristic wildlife includes white-tailed deer, moose, black bear, wolf, lynx, snowshoe hare, and chipmunk. Bird species include the hooded merganser, American black duck, wood duck, pileated woodpecker, mourning dove, cardinal, and wood thrush. Significant land uses include forestry, mining, and tourism. Low-intensity farming, primarily grazing operations, is scattered throughout much of the ecoregion (about 5% of the area). The major communities include Elliot Lake, Sudbury, North Bay, Parry Sound, and Huntsville. The population of the ecoregion is approximately 473 700.
This ecoregion is part of the Boreal Shield ecozone.