The Hell Hollow slender salamander (Batrachoseps diabolicus) is a species of salamander in the family Plethodontidae. It is endemic to California, in Mariposa County in western United States.
This salamander is endemic to the watersheds of the Merced River through to the American River, at elevations below 300m (1,000feet), on the western slope of the Sierra Nevada.
The Hell Hollow slender salamander is an IUCN Red List Vulnerable species.