The montane shrew is slightly larger and has a slightly longer tail than the vagrant shrew. It is distinctive in that the third unicuspid is smaller than the fourth.

It occurs as a small population near the Columbia River and along the Pacific Coast in Clackamas, Clatsop, Columbia, Hood River, Multnomah, and Tillamook counties and as a series of populations at higher elevations in Baker, Crook, Grant, Harney, Union, Wheeler, and Wallowa counties.