The fog shrew is the largest of the brown shrews in Oregon. Its range extends from Taft in Lincoln County east to near the eastern boundaries of Linn and Lane counties (except it is absent in the Willamette Valley) and southward along the west slope of the Cascade Range and in the Coast Range and Siskiyou Mountains. They are found in alder/salmonberry, riparian alder, and skunk cabbage marsh habitats and less often in conifer habitats.