[3] The 601,294-acre (243,335 ha) monument is one of the least-visited places in the National Park System due to its remote location and difficult weather.

A moderate eruption in 1931 forming Vent Mountain resulted in significant publicity, spurring studies to declare the region a national monument.

The monument and preserve were established within their final boundaries in 1980 with the passage of the Alaska National Interest Lands Conservation Act.

[5] The monument adjoins the Alaska Peninsula National Wildlife Refuge on its northeast and southwest sides.

The original mountain, about 7,000 feet (2,100 m) tall, collapsed into its magma chamber, leaving an approximate 3,300-foot (1,000 m) deep summit crater.

The elevation of the low point of the caldera floor, at the mouth of Surprise Lake and the beginning of the Aniakchak River, is approximately 1,055 feet.)

The monument and surrounding preserve include the volcanic feature, the wild Aniakchak River, the Bristol Bay coastal habitat, and portions of the coast of the Pacific Ocean.

The volcano's caldera presents an active volcanic and geothermal landscape and Surprise Lake, the source of the Aniakchak River.

The coastline region extends for 52 miles (84 km) along the southeastern side of the peninsula where it faces the Pacific Ocean.

Superimposed on the mountain chain are a series of volcanoes, the largest of which is the remnant of Mount Aniakchak, now largely collapsed into its caldera, the floor of which lies about 1,100 feet (340 m) above sea level.

On the southeast side, the rivers fall steeply through volcanic ash deposits where vegetation has largely recolonized the areas devastated by the volcano's eruption.

The weather is typically cloudy and windy, producing low ceilings and rough waters that make both aviation and boating hazardous.

Large terrestrial animals include caribou, Alaskan moose, brown bears, wolf packs and wolverines.

[10] The 1931 volcanic eruption at Vent Mountain within the crater disrupted plant communities around the volcano, which are now recovering and which are the subject of scientific research.

[11] The prehistory of the Aniakchak area is only beginning to come to light as a result of recent archaeological surveys funded by the National Park Service.

Archaeological data reveal that the entire central Alaska Peninsula was occupied, abandoned, and re-colonized numerous times, perhaps in response to recurrent catastrophic volcanism and subsequent processes of ecological succession.

Because there is ample evidence for human habitation in areas nearby, prior to the caldera-forming eruption, it is unlikely that the Aniakchak region was uninhabited.

However, the eruption fundamentally altered the landscape, and likely buried the pre-eruption evidence for human activity under many meters of volcanic debris.

Russian exploration of Alaska began in the mid-18th century, with fur traders arriving shortly afterwards to take advantage of the sea otters that populated the coast.

The first recorded mention of the Aniachak region appears in an 1827 atlas, which notes "Baie Amah-chak" and "Cap Kumlik."

[9] The development of the salmon fishing industry in Alaska brought a cannery to Chignik Lagoon in 1882, about 50 miles (80 km) southwest of the future monument.

The Alaska Packers' Association built a bunkhouse on Aniakchak Bay in the 1920s to house workers who maintained the trap and harvested fish during the summer months.

Detailed surveys established that the seeps did not exist, and that much of the region was composed of non-oil-bearing igneous rock, ending speculation.

[9] Father Bernard R. Hubbard was a Jesuit priest and professor of geology at Santa Clara University in California, who had been exploring Alaska's volcanoes and glaciers every summer season since 1927 and writing about them in best-selling books and in publications such as National Geographic and the Saturday Evening Post.

[16] A follow-up article by Barrett Willoughby in the Saturday Evening Post entitled "The Moon Craters of Alaska" discussed Hubbard's expedition to Aniakchak and nearby Mount Veniaminof in greater detail.

The same year a 1,500,000-acre (610,000 ha) Aniakchak Caldera National Recreation Area was proposed, extending to both sides of the peninsula and including Port Heiden on Bristol Bay.

Opposition from native groups and the presence of mining claims on some lands forced a scaled-back plan for Aniakchak Caldera National Monument that, at 580,000 acres (230,000 ha), was close to the present area.