It is found in the United States, inhabiting the lower Columbia River drainage in Washington, to Morro Bay in California.

The inland riffle sculpin was first formally described as Cottopsis gulosus by the French biologist Charles Frédéric Girard with its type locality given as the San Joaquin River in California.

[4] Inland riffle sculpins have a brown/tan coloration mottled with dark brown spots and reddish hues around their fins.

Spawning male riffle sculpins can be seen to have a darker appearance coupled with an orange hue at the edge of the first dorsal fin.

[8] Inland riffle sculpins maintain a diet primarily built of benthic invertebrates and active insect larvae.