Northern flying squirrels have thick light brown or cinnamon fur on their upper body greyish fur on the flanks and whitish fur underneath. They have large eyes and a flat tail. They can also be identified by their long whiskers, common to nocturnal mammals. Flying squirrels do not actually fly, they glide using a patagium created by a fold of skin. They are proficient gliders but uncoordinated walkers on the ground. They usually breed once a year in a cavity lined with lichen or other soft material. The northern flying squirrel is found across the top of North America, from Alaska to Nova Scotia, south to the mountains of North Carolina and Tennessee and west to Utah.

They prefer to live in areas with an abundance of conifer trees. They occur in large numbers in deciduous and mixed coniferous/deciduous forests. Other suitable habitats include areas, dominated by spruce, fir, and mixed hemlocks; beech-maple forests; areas with abundant growth of white spruce and birch, alternating with aspen groves. These nocturnal, arboreal rodents have thick light brown or cinnamon fur on their upper body and greyish fur on the flanks and whitish fur underneath. They have large eyes and a flat tail. They can also be identified by their long whiskers, common to nocturnal mammals.