The San Esteban Deermouse is a deer mouse described from San Esteban Island in the Gulf of California. Its original account compared its coat, tail, and hind feet with those of a close relative.
The original description says its color resembles Peromyscus eremicus, but its tail averages shorter and its hind foot is larger. Across four specimens, mean total length was 195 mm, tail 97 mm, and hind foot 22 mm.
The 1912 account lists two males and two females collected on San Esteban Island on April 14. It does not report diet, breeding, or behavior.
An extinction-risk assessment has not been added yet.