The Nass Ranges ecoregion is located in the Hazelton Mountains in west-central British Columbia. The topography is characterized by glacierized mountain peaks over 2700 m asl and broad valleys of the Skeena River and its tributaries. This ecoregion incorporates large areas of alpine and subalpine at higher elevations as well as warmer montane climate at lower elevations. The mean annual temperature for the major valleys is 4.5°C with a summer mean of 13°C and a winter mean of approximately -4.5°C. Mean annual precipitation is highly variable ranging from 2000 mm in the west to 1500 mm in the east where the climate is transitional to more interior conditions. The eastern portion of the ecoregion is characterized by closed stands of lodgepole pine, Engelmann spruce, and alpine fir forests in subalpine regions and by mature forests of interior western red cedar and western hemlock in the Skeena River valley. The western portion of the ecoregion has a more coastal climate wherein mountain hemlock dominates the subalpine and western hemlock the coastal forests of the lower Skeena River valley. The ecoregion, traversed by the deeply incised Skeena River valley, is largely underlain by folded Jurassic sediments and volcanic rocks with intrusions of igneous rocks in the south. Eutric Brunisolic and Gray Luvisolic soils are dominant in the eastern portion of the ecoregion, whereas Dystric Brunisolic and Humo-Ferric Podzolic soils dominate the milder, more humid western portion. Characteristic wildlife includes black-tailed deer, mountain goat, grizzly and black bear, and wolf. Forestry, recreation, hunting and fishing, and tourism are important land uses. Terrace, Hazelton and New Hazelton, are the main communities. The population of the ecoregion is approximately 24 300.
This ecoregion is part of the Pacific Maritime ecozone.