The Zacatecan deer mouse, or southern rock deermouse, (Peromyscus difficilis) is a species of rodent in the family Cricetidae. It is found only in Mexico, and is not considered endangered.
This species is known from west Chihuahua and southeast Coahuila, south to central Oaxaca, México (Musser and Carleton 2005). Its range follows the Sierra Madre Occidental and Oriental, and surrounds the deserts of Chihuahua and Sonora.