This species has a discontinuous distribution in west-central California, USA: coast ranges between Sonoma and Santa Barbara counties, Central Valley and surrounding foothills from southern Colusa County to north-western Kern County on the west side of the valley and southern Butte County to northern Tulare County on the east side. It has been eliminated from much of its former range in the Central Valley as a result of agricultural and urban development (Stebbins 1985b), but still occurs throughout most of its overall historical range and can be locally common (Trenham et al. 2000). About 80% of all extant occurrences are in Alameda, Contra Costa, Madera, Merced, Monterey, San Benito, and Santa Clara counties, with 30% of all occurrences in Alameda County. It has recently been rediscovered on the San Francisco Peninsula (Lagunita Lake, Stanford University) (Barry and Shaffer 1994). Jennings (1996; Herpetological Review 27:147) provides an old record from San Mateo County. It ranges from near sea level to 1,054m asl.