[3] The Eagle Cap Wilderness is characterized by high alpine lakes and meadows, bare granite peaks and ridges, and U-shaped glacial valleys.

[4] The Eagle Cap Wilderness and surrounding country in the Wallowa–Whitman National Forest was first occupied by the ancestors of the Nez Perce Indian tribe around 1400 AD, and later by the Cayuse, the Shoshone, and Bannocks.

Smaller mammals that inhabit the area year-round include the pika, pine martens, badgers, squirrels, and marmots.

Further surveys by the end of 2012 showed a count of at least seven wolves in a pack within the Upper Minam River area.

[13] Plant communities in the Eagle Cap Wilderness range from low elevation grasslands and ponderosa pine forest to alpine meadows.

Engelmann spruce, larch, mountain hemlock, sub-alpine fir, and whitebark pine can be found in the higher elevations.

Varieties of Indian paintbrush, sego lilies, elephanthead, larkspur, shooting star, and bluebells are abundant in the meadows.

[1] As Oregon's largest wilderness area, Eagle Cap offers many recreational activities, including hiking, backpacking, horseback riding, hunting, fishing, camping, and wildlife watching.

Several Alpine Huts and campsites are located throughout the McCully Basin, which are used as a base camp in the winter for telemark skiing.

[10] There are 47 trailheads and approximately 534 miles (859 km) of trails in Eagle Cap, accessible from Wallowa, Union, and Baker Counties, and leading to all areas of the wilderness.

16 miles (26 km) of the Lostine from its headwaters in the wilderness to the Wallowa–Whitman National Forest boundary are designated Wild and Scenic.