North Cascades National Park is located at the northernmost end of the North Cascades . Within the North Cascades there is also a divere faunal population including mammals , birds , reptiles and amphibians . Examples of amphibian species occurring in the North Cascades include Bufo boreas and the Rough-skinned newt , Taricha granulosa , whose population in the North Cascades has the unusual feature that approximately ninety percent of adults are perennibranchiate .