Siskiyou Mountains salamanders are similar to Del Norte salamanders, except they are a little shorter, growing to about five-and-a-half inches in total length. An adult salamander is brown with a light brown stripe along the back and a grayish-purple belly. It has light scattered flecks along the body. The Siskiyou Mountains salamander is a lungless salamander and breathes through its skin.
Siskiyou Mountains salamanders require talus (rock fragment piles) or rock outcrops in older forests. This salamander retreats deep within rocky crevices that remain cool and moist during the dry summer. Even during the rainy season, Siskiyou Mountains salamanders typically shelter under rocks and debris.