This species occurs in the western United States and northwestern Mexico. Its range extends from Washington and southwestern Idaho south through Oregon, California, Nevada, and western Utah to northwestern Baja California (Bell and Price 1996, Grismer 2002, Stebbins 2003), and disjunctly south to Isla de Cedros of the Pacific coast of Baja California (Grismer and Mellink, 1994). Its elevational range extends from sea level to about 3,353 m (11,000 feet) (Bell and Price 1996, Stebbins 2003).