This large ecoregion includes the western half of Melville Peninsula and much of northwestern coastal Baffin Island as far south as Nettilling Lake. The mean annual temperature is approximately -13°C with a summer mean of 0.5°C and a winter mean of -25°C. The mean annual precipitation ranges 100-200 mm. This ecoregion is classified as having a mid-arctic ecoclimate. Vegetation is discontinuous, and dominated by purple saxifrage, Dryas spp., and arctic willow, along with alpine foxtail, wood rush, and saxifrage. Dry sites are very sparsely vegetated, whereas wet areas have a continuous cover of sedge, cottongrass, saxifrage, and moss. The ecoregion takes in the mainland part of Melville Plateau physiographic region, a broad, gently warped, old erosion surface composed of crystalline Precambrian rocks that rise to about 460-610 m asl. It also takes in the very similar western portion of the uplands of Baffin Island where drainage begins to flow southwestward towards Foxe Basin. The plateau is divided into the Great Plain of the Koukdjuak with its broad belt of emerged, north-south- trending beaches in the centre, and the Soper Highland, north of Koukdjuak River. Bedrock outcroppings are common, and Turbic Cryosols developed on hummocky, thin, discontinuous sandy moraine are the dominant soils. Organic and Static Cryosolic soils also occur in this ecoregion. Most of the ecoregion is underlain by continuous permafrost with low ice content, although, in the area between Foxe Basin and Borden Peninsula, permafrost with medium ice content bisects the ecoregion north to south. Characteristic wildlife includes caribou, muskox, arctic hare, arctic fox, snowy owl, polar bear, seal, whale, and seabirds. Land uses include trapping, hunting, and fishing.
This ecoregion is part of the Northern Arctic ecozone.