Cascade barberry is often found in second growth below Douglas-fir or western redcedars. Leaf veins are fan-like hence the name nervosa. Leaflets on the plant are sharply toothed like holly, but not as shiny as for Berberis aquifolium (Tall Oregon grape). Both flowers and fruit are similar to the other Oregon grapes (sometimes spelled using a hyphen: Oregon-grapes).
This plant was first collected by the Lewis and Clark expedition in 1813. Some scientists place this and associated plants in the genus Mahonia.