[1][2] The Wehana–Tucannon Wilderness consists primarily of rugged basaltic ridges separated by deep canyons with steep slopes.

Subalpine fir, native grasses, and forbs are found at the highest elevations of the wilderness.

[1][3] The Wenaha–Tucannon Wilderness is home to a variety of wildlife, including Shiras moose,[4] Rocky Mountain elk, bighorn sheep, whitetail and mule deer, black bear, cougar, grey wolf,[5] coyote, snowshoe hare, rattlesnake, and pine marten.

Both the Tucannon and Wenaha Rivers provide spawning habitat for Chinook salmon and steelhead trout.

[1][3] Popular recreational activities in the Wenaha–Tucannon Wilderness include camping, horseback riding, wildlife watching, and hiking the area's 200 miles (320 km) of trails.