This ecoregion occupies the central portion of the Saint John River valley along the western border of New Brunswick. The ecoregion is marked by warm, moist summers and snowy, cold winters. The warmer climate is unique to western New Brunswick. The mean annual temperature is approximately 4.5°C. The mean summer temperature is 15°C and the mean winter temperature is -5°C. The mean annual precipitation ranges from 1000 mm to over 1200 mm. It is a sheltered enclave of temperate, deciduous forest made up of sugar maple, yellow birch, and beech and is associated with a sparse presence of white ash, butternut, ironwood, and basswood. Red spruce, red maple, balsam fir, and eastern hemlock are common softwoods. Poorly drained sites support white cedar, black ash, red maple, and white elm. Black spruce, balsam fir, and cedar can be found on scattered bogs. The ecoregion ranges in elevation 100-300 m asl and has developed on folded, calcareous, and argillaceous Palaeozoic strata. The uplands are remarkably uniform; concordant summits, whose regularity is broken only by a few hills and ridges, rise slightly above the general level. The Saint John River valley is deeply entrenched into them. The region is mantled with stony glacial till and small pockets of peatlands and fluvioglacial deposits. Loamy Humo-Ferric Podzols and Gray Luvisols are dominant soils. Gleysols are significant inclusions. Mesisols and some Humisols are found on swamps and fens. The region provides habitat for moose, black bear, white-tailed deer, red fox, snowshoe hare, porcupine, fisher, coyote, beaver, ruffed grouse, bobcat, raccoon, and muskrat. Hardwood lands have been extensively cleared for agriculture, including some orchards. Over a quarter of the ecoregion is in farmland. Forestry operations, including Christmas tree plantations, are also present. The major communities include Woodstock and Grand Falls. The population of the ecoregion is approximately 47 900.
This ecoregion is part of the Atlantic Maritime ecozone.