Adult frogs are gray or brown with yellow underbellies and thighs. Their color and grainy textured rough-looking skin helps camouflage them, making them hard to see among rocks. Adults can grow to three inches in length; males are slightly smaller than females.
Foothill yellow-legged frogs live in or along edges of permanent streams and rivers with exposed rocky streambeds and off-channel waters that are slow flowing and quiet. In summer, they are likely to hide under rocks in streams or among clumps of vegetation along pools. They use rocks or debris at the bottom of the streams as refuge from predators. They may wander out of their aquatic habitats on wet days. During times of cold weather, these frogs become inactive and usually reduce their level of activity during hot, dry weather.
The Foothill yellow-legged frog is an Oregon Conservation Strategy Species in several ecoregions - the Coast Range, Klamath Mountains, West Cascades and Willamette Valley.