The long-tailed vole usually is considered to be a medium-sized vole, although the size of an exceptionally large male may rival that of the largest Townsend's vole. The color of the dorsal pelage ranges from dull grayish through brownish gray to dark sepia brow. Those west of the Cascade Range have the darkest and richest-colored pelages. The sides are lighter and more grayish and the venter is grayish white to dull buff. The eyes and ears are large.
In Oregon, the long-tailed vole occurs in 30 of the 36 counties. It is absent from the Willamette Valley and other interior valleys west of the Cascade Range. Within its rang,e it occupies a diversity of habitats: coniferous forest, thickets, forest-meadow ecotones, riparian zones, marshes, and grassy or sagebrush areas.
Ordinarily, the long-tailed vole does not construct runways similar to those made by many other species of voles; an exception is in grassy areas. In areas vegetated by sagebrush or chaparral, it leaves little or no evidence of its presence.