President Calvin Coolidge proclaimed the area around Glacier Bay a national monument under the Antiquities Act on February 26, 1925.

[5] The national preserve encompasses 58,406 acres (91.3 sq mi; 236.4 km2) of public land to the immediate northwest of the park, protecting a portion of the Alsek River with its fish and wildlife habitats, while allowing sport hunting.

The National Park Service undertook an obligation to work with Hoonah and Yakutat Tlingit Native American organizations in the management of the protected area in 1994.

[7] The west side of the bay consists of a 26,000 feet thick sequence of Paleozoic sedimentary rocks, mainly massive limestones and argillite.

Sedimentary rocks of unknown age on the east side of Muir Inlet include tuff interbedded with limestone.

[8] Glacial advances occurred 7,000, 5,000 and 500 years ago, with the last extending to the entrance of the bay, where it left a huge semicircular terminal moraine.

The park's northwestern boundary, which also abuts Tongass National Forest, runs in the valley of the Alsek River to Dry Bay.

The plant hardiness zone at Glacier Bay Visitor Center is 7a with an average annual extreme minimum temperature of 4.2 °F (-15.4 °C).

[6] Within the park and preserve there are two Tlingit ancestral homelands that are of cultural and spiritual significance to living communities today.

[6] The Alsek River serves as a route of discovery and migration from the coastal mountain range in the park to the Pacific Ocean in the preserve.

Joseph Whidbey, master of the Discovery during the 1791–95 Vancouver expedition, found Icy Strait, at the south end of Glacier Bay, choked with ice in 1794.

[18] Scientists working in the park and preserve hope to learn how glacial activity relates to climate change.

[29] Regions of the park closest to the Gulf of Alaska have a relatively mild climate with significant rainfall and comparatively low snowfall.

[31] The park and preserve hosts many outdoor activities such as hiking, camping, mountaineering, kayaking, rafting, fishing, and bird-watching.

Typically hunted species in the preserve include black bears, mountain goats, wolves, wolverines, snowshoe hare, ptarmigans, waterfowls and a number of furbearers.

There is one big game hunting guide authorized through concession contracts to operate within Glacier Bay National Preserve.

Halibut are frequently esteemed by deep-sea fishers and in rivers and lakes Dolly Varden and rainbow trout provide sport.

An Alaskan sportfishing license is required for all nonresidents 16 and older, and residents 16–59, to fish in Alaska's fresh and salt waters.

[35] Evidence of human activity is scarce, because so much of the area is or was glaciated for much of the period and because advancing glaciers may have scoured all traces of historical occupation from their valleys.

[39] Muir's writings attracted the attention of William Skinner Cooper, an ecologist at the University of Minnesota, who saw the bay's retreating glaciers as an opportunity to study plant succession on the recently exposed land.

[41] Alaska game managers came under heavy criticism in the 1920s for a perceived lack of interest in protecting Alaskan brown bears.

The state approached the Park Service with a proposal to expand the boundaries of the Glacier Bay monument using land from Tongass National Forest as a bear sanctuary.

In the meantime, the Wrangell-St. Elias proposal was set aside in favor of expansions to the east for bear habitat and to the west to protect the Gulf of Alaska coastline.

President Franklin D. Roosevelt used the Antiquities Act to expand the monument on April 18, 1939, creating the largest unit in the national park system at the time.

An administrative site was also developed outside the monument boundaries at the Forest Service ranger station at Indian Point on Auke Bay, closer to Juneau.

Newmont Exploration Ltd. proposed the construction of a 3-mile (4.8 km) adit to an underground mine under the icefield, with a mill at the portal opening and a road to piers at Dixon Bay.

However, the final bill contained a number of significant exemptions, and the Newmont claim has never been resolved, although no mining activity has been proposed since the 1970s.

[45][46][47] As a result of the 1971 Alaska Native Claims Settlement Act (ANCSA), 80,000,000 acres (32,000,000 ha) of Alaskan public lands were eligible for inclusion in the national park system.

Facing an approaching deadline imposed by ANCSA to resolve land allotment and seeing delays in the proposed Alaska National Interest Lands Conservation Act (ANILCA) in Congress that was intended to make a final settlement, President Jimmy Carter used his authority under the Antiquities Act to proclaim fifteen National Park Service units in Alaska on December 1, 1978.

[48] The Kluane-Wrangell-St. Elias-Glacier Bay-Tatshenshini-Alsek transborder park system comprising Kluane, Wrangell-St Elias, Glacier Bay and Tatshenshini-Alsek parks, was declared a UNESCO World Heritage Site in 1979 for the spectacular glacier and icefield landscapes as well as for the importance of grizzly bears, caribou and Dall sheep habitat.