This ecoregion is the broad, level lowland plain that is drained by the Fort Nelson and Liard rivers in northeastern British Columbia, and the Hay River in northwestern Alberta, which all ultimately flow into the Mackenzie River in the Northwest Territories. The ecoregion is marked by short, warm summers and long, cold winters. The mean annual temperature is approximately -2.5°C. The mean summer temperature is 13°C and the mean winter temperature is -19°C. The mean annual precipitation ranges 350-450 mm. This ecoregion is classified as having a subhumid mid-boreal ecoclimate. It is characterized by closed mixed stands of trembling aspen, balsam poplar, white spruce, balsam fir, and black spruce on drier sites. Poorly drained fens and bogs, about 30% of the ecoregion, are covered with tamarack and black spruce. The ecoregion is composed of low-relief, flat-lying Palaeozoic strata near Great Slave Lake, and Cretaceous shale in its western section. Surface deposits are predominantly peat-covered clayey lacustrine and glacial till on nearly level to gently rolling topography. Gleysolic and Organic soils with some Organic Cryosols are dominant in the lowlands. Luvisols are the dominant upland soils. Sporadic discontinuous permafrost with low ice content is confined to organic deposits, and is characterized by sparse ice wedges. Characteristic wildlife includes moose, black bear, wolf, beaver, and snowshoe hare. Woodland caribou are found in some areas. The most species-rich habitats are the mixed woods and shrublands associated with the fens, bogs, ponds, streams, and lakes. Some pulpwood and local sawlog forestry, oil and gas extraction and exploration, water-oriented recreation, and wildlife trapping and hunting are the dominant uses of land in this region. The major communities include Hay River, Fort Simpson, and Fort Providence. The population of the ecoregion is approximately 13 200.
This ecoregion is part of the Taiga Plains ecozone.