This mouse is known only from Santa Catalina Island, Mexico. Records from the island include an animal seen active by day.
The back is pale cinnamon mixed with darker hairs, and the underside is white. The feet are cream-colored; the tail is darker above and nearly white below.
Field notes from 1931 record it active by day and captured at the bottom of a sandy draw. This single record does not show that it is always active by day.
An extinction-risk assessment has not been added yet.