The high country of northeast Washington is dominated by the densely-forested Okanogan Highlands, including the Selkirk Mountain Range. Separate from the Cascades, the mountains here are shielded from most Pacific Ocean weather patterns. The Selkirk Range, which extends into the far northeast comer of the state, is actually part of the Rocky Mountain system, with eroded topography and long mountain meadows.

Wildlife of the Okanogan Highlands reflects a transition between the Cascades and Rockies, with many wildlife species common to both, such as mule deer and white-tailed deer. The Selkirks provide habitat for Rocky Mountain species found nowhere else in Washington, including moose, woodland caribou, and the state's only fully-documented population of grizzly bears, listed as an endangered species.