The pelage of this mouse is grayish or brownish dorsally, the venter hairs are white with lead-colored bases, and the tail is light colored.

In Oregon, it occurs within the area circumscribed by a line connecting Denio Nevada; Fort Rock, Lake County; Powell Butte, Crook County; Malheur National Wildlife headquarters, Harney County; and Burns Junction, Malheur County.

On a daily basis, activity begins with an intense burst during the first light to hours after sunset, and declines to almost nil six hours after sunset, then, especially in summer, increases again before sunrise. The Dark Kangaroo Mouse constructs elaborate nests with cached seeds in its burrow system and sleeps on its back.