The California kangaroo rat is the largest kangaroo rat in Oregon, but is only of moderate size within the genus. It has a moderately broad face, relatively large ears, and awl-shaped lower incisors. The tail is 150 percent of the length of the head and body.

It is the darkest-colored kangaroo rat in Oregon. The pelage of the dorsum is composed of hairs with dark-gray bases, a narrow dark-buff band and black terminus. The venter, feet, upper lip,; and base, sides, and tip of tail are white and there is a white spot above each eye and behind each ear. A white stripe across each hind leg isolates a patch of dorsum-colored fur. A black moustache, eyelids and tail stripes and white and black splotched ears produce a striking attire for this handsome rodent.

In Oregon it occurs only in the southern portions of Jackson, Klamath and Lake County. It does not hibernate and may be active even when snow covers the ground or when it's raining. Activity is nocturnal, commencing shortly after dark. It constructs burrows as daytime retreats, often beneath boulders.