Prior to the park's establishment, isolated cabins were scattered around the region, the most well-known belonging to Richard Proenneke, whose films documenting his solitary life at Twin Lakes were made into Alone in the Wilderness in 2003.

Lake Clark was proclaimed a national monument by President Jimmy Carter using the Antiquities Act on December 1, 1978.

Lake Clark's status was changed to national park and preserve in 1980 by Congress, and about two-thirds was designated wilderness.

The extreme southwest section of the preserve includes Alaskan Native corporation lands, which are not open to the public.

Access is solely by air taxi or by boat along the Cook Inlet coast and Lake Clark.

Lake Clark Pass, at 1,050 feet (320 m) provides a way through the mountains by air at low elevation, and is the main route between Anchorage and western Alaska.

Glaciers have altered the mountains, carving cirques and U-shaped valleys into the range, which end abruptly on the east at the steep coast in deep bays or in outwash flats.

On the west the glaciers have cut deeply enough to create lakes, dammed by terminal moraines at their downstream ends.

10,197 feet (3,108 m) high, about 10 kilometres (6.2 mi) in diameter and with a volume of about 30 to 35 cubic kilometers, the stratovolcano rises through the Chigmit batholith.

The ash clouds affected air traffic, causing all four engines to fail on KLM Flight 867 when it passed overhead at 25,000 feet (7,600 m).

Like Redoubt, it stands on Jurassic granite basement rock, but has been significantly altered by glacial activity that has cut away the slopes on the southern and eastern sides.

According to the United States Department of Agriculture, the Plant Hardiness zone at Dick Proenneke's Cabin on Twin Lakes at 1988 ft (606 m) elevation is 2b with an average annual extreme minimum temperature of -43.0 °F (-41.7 °C).

[22] The park and preserve offer a variety of possible activities, including kayaking, rafting, fishing, bird-watching, hiking and camping.

[27] Lake Clark preserves a wide variety of Alaskan landscapes and ecosystems, corresponding to its four main physiographic areas.

[29] Boreal forest dominates the lower sections of the southwest part of the park, with white and black spruce making up most of the coniferous trees.

They account for under 1% of the park's area, but provide a source of food in early summer for both brown and black bears.

[32] Lake Clark's coastal areas are rated as some of the top bear viewing destinations in the world, along with the coast of Katmai National Park.

Smaller mammals include coyotes, marten, Arctic and red foxes, wolverine, river otter, beaver and Canadian lynx.

A recent survey found that about 219 bears graze in salt marshes during the summer in the coastal areas of the park.

Kijik village is the primary archaeological site in the park, inhabited by Dena'ina until the early 20th century.

By the 1890s American traders had arrived in the area, meeting a native population that had been greatly reduced by imported diseases.

[41] Apart from Port Alsworth, there are five other communities near but not within the park: Lime Village, Nondalton, Iliamna, Newhalen and Pedro Bay.

[42] During the 20th century the future park area was lightly populated by people with a high tolerance for solitude.

Proenneke lived at Twin Lakes from 1968 to 1999 in a cabin he built himself, feeding himself through subsistence hunting and by salvaging meat from animals left by sport hunters.

[43][44] Proenneke's cabin is now owned by the park service and listed on the National Register of Historic Places.

[45] Lake Clark was proclaimed a national monument on December 1, 1978, by President Jimmy Carter, using his authority under the Antiquities Act.

[47] The 2,619,550-acre (1,060,090 ha) Jay S. Hammond Wilderness covers much of the park's area, excluding preserve lands and the Cook Inlet coast.