Anticosti Island is an outlier of the boreal forest in the Gulf of St. Lawrence. The ecoregion is marked by cool rainy summers and cold winters. It is modified by its maritime exposure and the influence of the Labrador current. The mean annual temperature is approximately 1.5°C. The mean summer temperature is 11.5°C and the mean winter temperature is -9°C. The mean annual precipitation ranges 800-1000 mm. This ecoregion is classified as having a perhumid mid-boreal ecoclimate. It is dominated by stands of black spruce with lesser amounts of balsam fir and an understory of moss. Paper birch and aspen occur sporadically on disturbed sites, whereas jack pine occurs on drier sites. The island is about 200 km long with a maximum width of about 56 km. It is a south-dipping cuesta of Palaeozoic carbonate strata. Relief is generally low with elevations seldom reaching 150 m asl. Wave-cut terraces up to 60 m in elevation occur on both north and south shores, being generally wider on the south side. Humo-Ferric Podzolic soils developed on rolling, sandy loam, morainal deposits are dominant in the ecoregion. White-tailed deer, black bear, wolf, fox, lynx, hare, grouse, waterfowl, and shorebirds are characteristic wildlife. Forestry, hunting, and trapping are major uses of land on the island. The population of the ecoregion is approximately 300.
This ecoregion is part of the Boreal Shield ecozone.