This irregularly shaped unit is largely Stephen Mather Wilderness within Cascades National Park. The eastern portion along Road 20 offers hunting access, but there is some very steep, rugged, roadless country in the Okanogan National Forest on the western Cascade Range. Mount Ballard, Majestic Mountain and McKay Ridge running parallel dissect this chunk of forest running almost north to south. Elevation changes of 2,000-ft in 900-yards are common. The western slopes offer the thickest cover, which blacktail deer prefer. There are a few tiny pieces of private land in the eastern tip, so carry your GPS when hunting these ridges. Hunting is also allowed in the Ross Lake National Recreation Area in the southern tip region along McAllister and Thunder Creek valleys, offering a modest elevation change.

Although no official surveys have been conducted, biologist observations and other anecdotal reports support the general idea that blacktail deer numbers are down.

Ruby Mountain, in the middle of the GMU, rises to 7,303-ft, however, the bulk of this irregular star shaped unit follows the major drainages and low ground, including Diablo and Ross Lake. This steep, rugged, heavily forested country is best suited for hardcore hunters willing to burn boot leather for a backcountry hunting adventure.

There is decent public access, although accessing the backcountry is not very easy as much of the hunting areas are roadless.

This unit holds old growth forests pinwheeled by Ruby Mountain, and big drainage spokes pointing out in all directions. Large dams fill the drainages holding precious water for civilization just to the west. Forests are thicker the farther west you go when compared to the more arid eastern side with fairly open eastern facing slopes and dark timber dominating the west slopes.

Primitive camping on National Forest land is allowed for the majority of the year, but various fire bans and forest road closures may happen, so double check any restrictions or permits necessary prior to your trip. There are no nearby towns with hotels, fuel, and food.