Stephen Mather Wilderness in the context of "Glacier Peak Wilderness"

Wilderness or wildlands (usually in the plural) are Earth's natural environments that have not been significantly modified by human activity, or any nonurbanized land not under extensive agricultural cultivation. The term has traditionally referred to terrestrial environments, though growing attention is being placed on marine wilderness. Recent maps of wilderness suggest it covers roughly one-quarter of Earth's terrestrial surface, but is being rapidly degraded by human activity. Even less wilderness remains in the ocean, with only 13.2% free from intense human activity.

Some governments establish protection for wilderness areas by law to not only preserve what already exists, but also to promote and advance a natural expression and development. These can be set up in preserves, conservation preserves, national forests, national parks and even in urban areas along rivers, gulches or otherwise undeveloped areas. Often these areas are considered important for the survival of certain species, biodiversity, ecological studies, conservation, solitude and recreation. They may also preserve historic genetic traits and provide habitat for wild flora and fauna that may be difficult to recreate in zoos, arboretums or laboratories.

The Pasayten Wilderness is a 531,539 acres (215,106 ha) protected area located within Okanogan–Wenatchee National Forest and Mount Baker National Forest in Washington state, centered on the Three Forks (48°54′02″N 120°38′01″W / 48.900584°N 120.6336808°W / 48.900584; -120.6336808) of the Pasayten River, a tributary of the Similkameen River. Although part of the wilderness lies in Mount Baker-Snoqualmie National Forest, the largest section falls within the boundaries of Okanogan National Forest, which has responsibility for the wilderness's management. The wilderness is bordered by the Stephen Mather Wilderness to the west. The northern boundary of the wilderness is the Canada–US border. Across the border are Manning Provincial Park and Cathedral Provincial Park. The wilderness area is adjacent to the Ross Lake National Recreation Area to the west, and North Cascades National Park beyond that. The Pacific Crest National Scenic Trail has its northernmost section in this wilderness. The western part of the wilderness features dramatic views and peaks of the northern Washington Cascade Mountains while the eastern section is known for its grasslands and Alpine tundra. The tallest point in the Pasayten is Jack Mountain.

The Pasayten is traditional hunting territory of the Nlaka'pamux peoples of the Fraser Canyon and Nicola Country along with adjoining parts of the Cascade Range, although there are no Nlaka'pamux populations on the Washington side of the border.

Mount Baker Wilderness is a 119,989-acre (48,558 ha) wilderness area within the Mount Baker-Snoqualmie National Forest in the western Cascade Range of northern Washington state. Its eastern border is shared with the boundary of the Stephen Mather Wilderness and North Cascades National Park for a distance of 40 miles (65 kilometers). The wilderness extends from State Route 20 north to the Canada–US border. On the west, it is bounded by the foothills of the Puget Sound lowlands.

Almost entirely within Whatcom County, the wilderness lies on the western slopes of the Cascade Mountains. The three forks of the Nooksack River and the Baker River are the major drainages of the wilderness.

The Lake Chelan-Sawtooth Wilderness is a 153,057-acre (61,940 ha) protected wilderness area located within the Okanogan and Wenatchee national forests in Washington State. The wilderness borders Lake Chelan National Recreation Area and North Cascades National Park and the Stephen Mather Wilderness to the northwest. It was designated with the passage of the Washington Wilderness Act of 1984, on lands occupied by the old Chelan Division of the Washington Forest Reserve, now part of both the Okanogan and Wenatchee national forests.