Columbia National Wildlife Refuge in central Washington lies within the Drumheller Channeled Scablands, where cliffs, canyons, lakes, sagebrush grasslands, and lava-flow remnants reveal a long geologic history shaped by fire, ice, floods, and volcanic activity. Its northern half south of Potholes Reservoir contains the deeply eroded Drumheller Channels, designated a National Natural Landmark in 1986 and regarded as an exceptionally dramatic erosional landscape. Although the refuge lies in the Cascade Mountains’ rain shadow and receives less than eight inches of rain annually, water from the Columbia Basin Project sustains lakes and wetlands that support abundant wildlife, including migratory waterfowl and mammals from river otters to cougars.