Aniakchak National Monument and Preserve Photo: Game McGimsey, Alaska Volcano Observatory / USGS / Public domain
United States › Alaska

Aniakchak National Monument and Preserve

ByWilderness Experts

Aniakchak is a volcanic caldera 6 miles (10 km) wide on the Alaska Peninsula, one of the least-visited places in the National Park System. There are no roads, trails or facilities; visitors fly in, hike across the crater and float the Aniakchak River to the Pacific.

Fast facts

  • Established: 1978; monument and preserve since 1980
  • Size: about 600,000 acres (2,430 km²)
  • Caldera: 6 miles (10 km) wide and up to 2,500 feet (762 m) deep, formed about 3,500 years ago
  • Last eruption: 1931
  • Gateway: King Salmon, Alaska, 450 miles (720 km) southwest of Anchorage
  • Managed by: the National Park Service

The landscape

Inside the caldera, lava flows, cinder cones and Vent Mountain surround Surprise Lake, whose outflow breaks through the crater wall at a gap called The Gates to form the Aniakchak River. Outside, tundra and brush slope to the Bering Sea and the Pacific. Brown bears and caribou roam, and the weather is dominated by wind, rain and fog.

Best time to go

June to August is the only practical season, and even then storms, wind and fog are the norm. Plan for flights to be delayed by days.

Surprise LakePhoto: Tahzay Jones, National Park Service · Public domain · via Wikimedia Commons
Vent MountainPhoto: Katmai National Park and Preserve · Public domain · via Wikimedia Commons
Half ConePhoto: Katmai National Park and Preserve · Public domain · via Wikimedia Commons
The GatesPhoto: Katmai National Park and Preserve · Public domain · via Wikimedia Commons
Mount AniakchakPhoto: Unknown · Public domain · via Wikimedia Commons
Aniakchak BayPhoto: Katmai National Park and Preserve · Public domain · via Wikimedia Commons
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Getting there and around

There are no roads. Air taxis fly from King Salmon and other Alaska Peninsula towns, landing on Surprise Lake or on beaches when weather allows. Drop-offs and pickups are often delayed by weather.

Things to do

This is an expedition, not a day trip. Hikers explore the caldera floor, climb Vent Mountain and camp among the volcanic features.

Paddlers carry packrafts or folding boats to float the Aniakchak River, a designated Wild River, from Surprise Lake through The Gates and down to Aniakchak Bay on the Pacific, a trip of several days with rapids in its upper section.

Staying safe

Weather is the greatest danger: high winds, cold rain and fog can pin you down for days, so carry extra food and a shelter that can stand in gales. Brown bears are common: carry bear spray and use bear-resistant food containers. Help is far away; carry a satellite messenger.

Know before you go

There are no fees, facilities, trails or rangers on site. Leave a detailed trip plan with the park and your air taxi. This page is a general overview, not a live conditions report, so confirm conditions with the National Park Service before you go.

Navigation
Coordinates
56.8570, -157.7519
Magnetic declination
11.0° E (2026)

Set this declination on your compass, then align it to the map's north lines; it is the angle between true north and magnetic north, refreshed each year.

How declination works, and how to navigate with a map and compass

14 places in Aniakchak National Monument and Preserve

A spread of the park’s main places shows straight away, and the rest appear as you zoom in. You can also search above, or pick any place from the lists below, and the map will go to it. Places in bold, marked , have a short description.

Sights 14

Lakes

Points of interest

Peaks 10

Map data comes from third-party sources and may be incomplete or out of date, so carry a current official map (terms).

Trip types
Multi-day/expeditionBackcountryPackraftingWildlife viewing

Looking for one of these closer to home?Destinations near me by trip type →

Terrain
MountainsLakesRiversArctic tundraCoast
Key hazards
Extreme wind and stormsWeather-delayed flightsBrown bearsCold waterTotal remoteness
Best seasons
Summer (June to August)
Difficulty
Strenuous (remote wilderness)
Access / trailheads
Air taxi only, from King Salmon and Alaska Peninsula towns, weather permitting. No roads.
Water
Plentiful; treat all water.
Cell / satellite coverage
None. Carry a satellite messenger.
Nearest ranger / SAR / emergency
Emergencies: 911 via satellite messenger. Katmai, Aniakchak and Alagnak office (King Salmon): 907-246-3305.
Permits & regulations
No fees. No facilities; leave a trip plan with the park.
Leave No Trace
Store food in bear-resistant containers, camp on durable ground away from the lake shore, and pack out everything.
Conditions by month

October This month

Average high43°F(6°C)6°C(43°F)
Average low28°F(−2°C)−2°C(28°F)
Rain and snow, as water2.9 in(73 mm)73 mm(2.9 in)
Daylight, mid-month10 h 27 minSunrise 9:03 a.m., sunset 7:30 p.m.
  • Below-freezing nights

What to bring depends on your trip: how long you’re out, where you sleep, and how far you go from the road. The planner builds the list for yours.

Plan a trip here →

Averages for 1991–2020 from NOAA U.S. Climate Normals, measured at the King Salmon station, 115 miles (186 km)186 km (115 miles) away at 661 feet (201 m)201 m (661 feet). That is the nearest station with long-term records, so treat these as a regional guide. Higher trails run colder, by about 3.5°F for every 1,000 ft (2°C per 300 m)2°C for every 300 m (3.5°F per 1,000 ft) of climb. Daylight runs from sunrise to sunset on the 15th, on the park’s own clock, for a level horizon. Valleys and slopes facing away from the sun are in shade earlier.

Before you go Conditions, permits, fire bans and closures change constantly — we summarise and link out, but always confirm with the managing agency first.
Official monument website → Last verified 2026-09-30

Nearby parks

Straight-line distance between park centres. Road distance is usually longer.

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