The United States has 161 potentially active volcanoes across 12 states and territories — more than any other country on Earth. They span Alaska's Aleutian chain, Hawaii's hotspot shield volcanoes, the Cascade Range from Washington to California, and the Yellowstone supervolcano in Wyoming. The USGS rates 18 of them "very high threat."
Active Volcanoes
161
Very High Threat
18
Currently Erupting
1-2
States w/ Volcanoes
12
How Many Volcanoes Are in the US?
The US has about 161 potentially active volcanoes, according to the USGS Volcano Hazards Program. That's more than Indonesia (~130), more than Japan (~111), and more than any other country. Most Americans don't realize this. The number surprises people because 80+ of those volcanoes sit in Alaska's remote Aleutian Islands, where eruptions happen regularly and nobody notices.
But the ones that do get noticed can be catastrophic. The 1980 eruption of Mount St. Helens killed 57 people, flattened 230 square miles of forest, and sent ash across 11 states. Mount Rainier looms over the Seattle-Tacoma metro area (4 million people), and the USGS considers it the most dangerous volcano in the country because of the lahar threat. Kilauea has been erupting on and off since 1983, making it the most active volcano on Earth. And then there's Yellowstone — the supervolcano that last blew 640,000 years ago with a VEI 8 eruption that buried half of North America in ash.
By VolcanoDB Research Team. Data: USGS Volcano Hazards Program, Smithsonian Global Volcanism Program.
US Volcanoes by State: A Complete Guide
American volcanoes aren't randomly scattered. They follow tectonic boundaries and hotspot tracks in distinct clusters. Alaska dominates the count, but every volcanic state has its own character. Here's the breakdown.
80+
Alaska — The Aleutian Volcanic Arc
Alaska has more volcanoes than all other US states combined. Over 80 potentially active volcanoes stretch along the 1,550-mile Aleutian arc, where the Pacific Plate subducts beneath the North American Plate. This is part of the Pacific Ring of Fire, and it's one of the most volcanically active stretches on Earth.
Pavlof has erupted over 40 times since 1790 — making it the most active volcano in the Aleutians. Shishaldin is the most perfectly symmetrical cone in the chain and erupted violently in 2023-2024, with ash columns reaching 40,000+ feet. Cleveland was essentially unmonitored until 2014 despite erupting frequently — it's that remote. Redoubt and Augustine in Cook Inlet pose the greatest risk to Anchorage. Most Aleutian eruptions affect nobody on the ground but can shut down transpacific air routes — volcanic ash and jet engines don't mix.
Hawaii's volcanoes are fundamentally different from every other US volcano. They sit over a mantle hotspot, not on a plate boundary. The magma is basaltic — fluid, effusive, producing shield volcanoes rather than explosive stratovolcanoes. That's why Hawaiian eruptions produce rivers of lava rather than pyroclastic flows.
Kilauea is the most active volcano on Earth and has been erupting episodically since 1983. The 2018 lower East Rift Zone eruption destroyed over 700 homes in Leilani Estates. Summit eruptions in Halemaumau crater have continued through 2024-2026. Mauna Loa, the world's largest active volcano by volume, ended a 38-year silence in November 2022 when lava flows from the northeast rift zone advanced toward Hilo before stopping. Mauna Kea (4,205m) is technically taller but has been dormant for roughly 4,500 years. Hualalai last erupted in 1801 and sits beneath Kailua-Kona, and Haleakala on Maui last erupted around 1600.
Washington has the most dangerous concentration of volcanoes in the Lower 48. Five major stratovolcanoes line the state from north to south: Baker, Glacier Peak, Rainier, Adams, and St. Helens. Three of them rank in the USGS top 15 "very high threat" list.
Rainier (14,411 ft) is the USGS's #1 most dangerous volcano in America. Not because it erupts often, but because 80,000+ people live directly in lahar runout zones. The Osceola Mudflow 5,600 years ago traveled 70 miles to Puget Sound. Today that path goes through Orting, Puyallup, Sumner, and Auburn. St. Helens (8,363 ft) needs no introduction — the May 18, 1980 lateral blast was the deadliest and most economically destructive volcanic event in US history. It's still rebuilding its lava dome. Baker (10,781 ft) had increased steam emissions in 1975 that worried scientists, and it's visible from downtown Seattle on clear days. Glacier Peak (10,541 ft) is the most remote of the Washington Cascades but has produced some of the largest eruptions in the range, including multiple VEI 5 events.
Oregon sits in the heart of the Cascade volcanic arc and has more "very high threat" volcanoes (4) than any state except Alaska. Mount Hood (11,240 ft) is Oregon's highest peak and the most-climbed glaciated peak in the US, with roughly 10,000 summit attempts per year. Its last eruption around 1866 was minor, but the volcano has a pattern of producing lahars and pyroclastic flows.
Crater Lake is the remnant of Mount Mazama, which produced a cataclysmic VEI 7 caldera-forming eruption roughly 7,700 years ago. The resulting lake (1,949 ft deep) is the deepest in the US. Three Sisters has had measurable ground uplift since 1998 — about 3 cm per year — indicating magma intrusion at depth. That's not an imminent eruption sign, but it's being closely watched. Newberry Volcano is a massive shield-shaped caldera with spectacular obsidian flows from its most recent eruption around 700 CE.
California — Cascades Meet the Long Valley Supervolcano
California's volcanic hazards get overshadowed by earthquakes, but the state has three "very high threat" volcanoes. Mount Shasta (14,179 ft) is the tallest volcano in the Cascade Range and one of the most beautiful mountains in the US — a massive stratovolcano with a satellite cone (Shastina) that's itself taller than most Cascade peaks. It last erupted around 1250 CE.
Lassen Peak holds the distinction of the most recent Cascade eruption before St. Helens — it erupted from 1914 to 1917, with a massive blast on May 22, 1915 that devastated the northeast slope and sent a lahar 20 miles downstream. The volcanic landscape is now preserved as Lassen Volcanic National Park. Long Valley Caldera in eastern California is a supervolcano that produced a VEI 7 eruption 760,000 years ago, creating the 20-mile-long caldera and depositing the Bishop Tuff across much of the western US. The caldera has been in a state of unrest since 1978, with uplift, swarms of earthquakes, and CO2 emissions that killed trees near Mammoth Mountain. The Mono Craters, a chain of volcanic domes along the caldera's edge, last erupted around 1350 CE.
Yellowstone is the most famous volcano in America, and for good reason. The caldera measures 34 by 45 miles and sits atop a mantle plume that has produced three supereruptions: 2.1 million years ago (Huckleberry Ridge Tuff, VEI 8), 1.3 million years ago (Mesa Falls Tuff), and 640,000 years ago (Lava Creek Tuff, VEI 8). That last event ejected roughly 240 cubic miles of material.
But here's what the clickbait articles don't tell you: the odds of another supereruption in any given year are roughly 1 in 730,000. The USGS Yellowstone Volcano Observatory monitors over 2,000 earthquakes per year in the park, and current data shows no signs of an impending eruption. The most recent volcanic activity at Yellowstone was a lava flow roughly 70,000 years ago. The geysers, hot springs, and fumaroles (including Old Faithful) are impressive evidence of the heat below — but they're actually releasing pressure, not building toward a blast.
Nearby, Idaho's Craters of the Moon is a massive basaltic lava field from the same hotspot track — the last eruption there was about 2,000 years ago.
Other Volcanic States — Arizona, New Mexico, Utah, Colorado, Idaho
Volcanic activity extends well beyond the usual suspects. Arizona's Sunset Crater erupted around 1085 CE — less than a thousand years ago — and the San Francisco volcanic field near Flagstaff contains over 600 volcanic vents. New Mexico's Valles Caldera is a 13.7-mile-wide supervolcano that last erupted about 68,000 years ago and is now a national preserve. Colorado has Dotsero, a maar volcano that erupted roughly 4,200 years ago — the only Holocene eruption in the state. Utah has volcanic fields in its western desert. Idaho has Craters of the Moon (a monument) and the track of the Yellowstone hotspot running across the Snake River Plain.
None of these are considered high-threat by the USGS, but they're a reminder that volcanism in the western US isn't limited to the Cascades and Alaska. The Basin and Range province is tectonically active, and future eruptions in these areas aren't impossible — just unlikely in our lifetimes.
USGS Very High Threat Volcanoes: The Top 18
The USGS assigns every US volcano a "threat score" based on 24 factors including eruption frequency, proximity to population, aviation exposure, and historical fatalities. Volcanoes scoring above a certain threshold are classified as "very high threat" and receive the most monitoring resources. Here are all 18, with links to their full database pages.
Notice the pattern: Alaska and the Cascades dominate the top 18. Alaska contributes 6, Oregon contributes 4, Washington contributes 4, Hawaii has 2, and California rounds it out with 2. I've hiked to several of these summits, and the contrast is striking — Rainier looks like a postcard from the Seattle skyline, but up close the glaciers are deeply crevassed and the sulfur vents at the summit smell like something's cooking underneath. It is. For a broader look at the world's most dangerous peaks, see our most dangerous volcanoes guide.
Notable US Volcanoes in Our Database
Beyond the USGS threat rankings, here are 15 notable American volcanoes from our database — spanning every volcanic state. Each links to its full page with eruption records, coordinates, and real-time monitoring data.
As of May 2026, the USGS is monitoring elevated activity at several US volcanoes. The color-coded aviation alert system ranges from Green (normal) through Yellow (advisory), Orange (watch), to Red (warning — eruption in progress with significant ash emission).
Kilauea, Hawaii — Episodic Summit Eruptions (2024-2026)
Kilauea has been erupting episodically since its dramatic return to activity in September 2023. Summit eruptions within Halemaumau crater have produced lava lakes and fountains reaching 200+ feet. The eruptions follow a pattern: weeks to months of inflation as magma fills the summit reservoir, then brief (hours to days) eruptions that drain it. The 2018 lower East Rift Zone eruption destroyed 716 homes and added 875 acres of new land to Hawaii's coastline. Current activity is confined to the summit. Read our full Kilauea eruption guide for the latest.
Yellowstone Caldera — Ongoing Monitoring
Yellowstone isn't erupting and isn't about to. But it's the most monitored volcano on Earth, and the data is worth knowing. The Yellowstone Volcano Observatory records roughly 1,500-2,500 earthquakes per year inside the caldera, mostly too small to feel. The caldera floor has been subsiding since 2015 after years of uplift. Steamboat Geyser, the world's tallest active geyser, erupted 48 times in 2018 after decades of silence — then went quiet again. None of this signals an impending eruption. Read our Yellowstone volcano guide for more.
Aleutian Volcanoes — Frequent Low-Level Activity
Alaska's Aleutian volcanoes routinely produce minor eruptions that go unnoticed by most Americans. Shishaldin had a major eruption sequence in 2023-2024 with ash reaching 40,000+ feet. Cleveland is frequently at elevated alert status. The Alaska Volcano Observatory (AVO) tracks all Aleutian activity because eruptions directly threaten North Pacific and transpacific flight routes — the Great Circle route from the US West Coast to Asia passes directly over the Aleutians.
Visiting America's Volcanoes: National Parks and Monuments
The US has the best volcano tourism infrastructure in the world. Six national parks and one national volcanic monument are built around volcanic features, all with paved roads, visitor centers, and maintained trail systems. I've hiked to several of these summits, and they're among the best outdoor experiences in America. For more volcano hiking worldwide, see our volcano hiking guide.
Hawaii Volcanoes National Park
Home to Kilauea and Mauna Loa, two of the world's most active volcanoes. Walk across the Kilauea Iki crater floor, see the Thurston Lava Tube, and drive the Chain of Craters Road to where lava met the sea. During active eruptions, you can sometimes watch lava fountaining from designated overlooks. The park spans from sea level to 13,681 ft at Mauna Loa's summit.
The most glaciated peak in the contiguous US, with 25 named glaciers covering 36 square miles. Rainier looks serene, but the USGS ranks it as America's most dangerous volcano because lahars could reach Puget Sound communities in under an hour. The Wonderland Trail circumnavigates the entire mountain in 93 miles. Paradise, on the south side, holds the US record for annual snowfall (1,122 inches in 1971-72).
The deepest lake in the United States (1,949 ft) sits inside a caldera formed by a VEI 7 eruption of Mount Mazama roughly 7,700 years ago. The eruption ejected 12 cubic miles of material. Wizard Island, a cinder cone rising 755 ft above the lake surface, formed after the caldera collapse. The water is stunningly blue because it's fed entirely by rain and snowmelt with no inlet streams.
The site of the most recent volcanic eruption in the Cascades before Mount St. Helens. Lassen Peak erupted from 1914 to 1917, with a massive blast in May 1915 that devastated the northeast slope. Today the park has all four types of volcanism: plug dome, shield, cinder cone, and stratovolcano. Bumpass Hell, a hydrothermal area with boiling springs and fumaroles, is the park's signature hike.
Sitting atop the Yellowstone hotspot, the park contains the world's largest collection of geysers (including Old Faithful), hot springs, and fumaroles. The caldera measures 34 by 45 miles and last produced a lava flow roughly 70,000 years ago. Three supereruptions (VEI 8) in 2.1 million years. The USGS monitors over 2,000 earthquakes per year here, but the odds of another supereruption in our lifetimes are roughly 1 in 730,000.
The blast zone from the May 18, 1980 eruption is preserved as a monument, not a national park. The Johnston Ridge Observatory sits 5 miles from the crater and offers a direct view into the horseshoe-shaped amphitheater. The eruption killed 57 people, flattened 230 square miles of forest, and sent an ash column 80,000 feet into the atmosphere. The lava dome has been slowly rebuilding since 2004.
Beyond the parks, you can hike to the summit of several Cascade volcanoes with varying levels of difficulty. Mount St. Helens requires a permit ($15) and is a strenuous but non-technical dayhike. Mount Adams is a glacier climb requiring crampons. Rainier requires mountaineering experience and typically a 2-day summit attempt. Hood is the most-climbed glaciated peak in America but has killed more climbers than any other Oregon mountain. Always check conditions with the USGS and local ranger stations. For a complete rundown, explore our interactive volcano map to find volcanoes near your location.
Types of Volcanism in the United States
The US is unusual in having nearly every type of volcanism represented within its borders. Understanding the differences matters because each type produces different hazards.
Subduction Zone (Cascades, Alaska)
100+
The Pacific Plate subducts beneath North America, creating the Cascade Range and Aleutian Arc. Produces explosive stratovolcanoes — the most dangerous type. St. Helens, Rainier, Shasta, Redoubt.
Hotspot (Hawaii, Yellowstone)
~10
Mantle plumes punch through the plate, creating shield volcanoes (Hawaii) or supervolcanoes (Yellowstone). Hawaii's basaltic eruptions are effusive. Yellowstone's silicic magma is explosive.
Continental Rift (Basin and Range)
20+
Extensional tectonics in the western US thin the crust enough for magma to reach the surface. Produces cinder cones, maars, and basalt flows. Sunset Crater, Dotsero, Craters of the Moon.
Caldera Systems
5+
Large silicic magma chambers that produce catastrophic eruptions followed by collapse. Yellowstone, Long Valley, Crater Lake (Mazama), Newberry, Valles. Some of the biggest eruptions in Earth's history.
The Cascade stratovolcanoes are the most dangerous to populated areas because they produce explosive eruptions with lahars, pyroclastic flows, and ash fall. Hawaiian eruptions are spectacular but rarely fatal — lava moves slowly enough to evacuate. The real wildcard is the caldera systems: Yellowstone, Long Valley, and Crater Lake (Mazama) have all produced eruptions that reshaped entire regions. A VEI 8 Yellowstone eruption would be a civilization-altering event — but again, the annual probability is about 1 in 730,000. Sleep well.
Explore All US Volcanoes in Our Database
Every American volcano with eruption history, coordinates, USGS alert levels, and real-time seismic data
The United States has approximately 161 potentially active volcanoes, according to the USGS Volcano Hazards Program. This makes the US the country with the most active volcanoes on Earth, narrowly ahead of Indonesia (~130) and Japan (~111). The count includes 80+ in Alaska's Aleutian chain, 13 in the Cascade Range, 5 in Hawaii, and scattered volcanic fields across the western states. The USGS defines 'potentially active' as volcanoes that have erupted in the Holocene (last 11,700 years) and could reasonably erupt again.
What is the most dangerous volcano in the US?
Mount Rainier in Washington is ranked by the USGS as the most dangerous volcano in the United States due to the extreme lahar risk. Over 80,000 people live in lahar hazard zones along river valleys that drain the mountain, and a major eruption-triggered lahar could reach the Puget Sound lowlands in as little as 30-45 minutes. Kilauea has the highest overall threat score (263) because it erupts so frequently, but Rainier poses a greater risk of mass casualties from a single event. Mount St. Helens (57 killed in 1980) is the most recently destructive.
Which US state has the most volcanoes?
Alaska has by far the most volcanoes of any US state, with over 80 potentially active volcanoes — mostly along the 1,550-mile Aleutian volcanic arc. Alaska accounts for roughly half of all US volcanoes. After Alaska, the states with the most volcanoes are: Washington (5 major Cascade volcanoes plus volcanic fields), Oregon (7+ Cascade volcanoes including Crater Lake), California (7+ including Shasta, Lassen, and Long Valley Caldera), and Hawaii (5 major shield volcanoes across the island chain).
Has a volcano erupted in the US recently?
Yes. Kilauea in Hawaii has been erupting episodically throughout 2024-2026, with summit eruptions producing lava fountains and lava lakes within Halemaumau crater. Mauna Loa erupted in November 2022 for the first time since 1984, sending lava flows down the northeast rift zone toward Hilo before stopping. In Alaska, Shishaldin erupted violently in 2023-2024 with ash columns reaching 40,000+ feet. Mount St. Helens last erupted in 2004-2008 (dome-building), and a full Cascade eruption hasn't occurred since 1917 (Lassen Peak).
Can you visit volcanoes in the US?
Absolutely. The US has some of the most accessible volcano tourism in the world, much of it within national parks with excellent infrastructure. Hawaii Volcanoes National Park lets you walk across crater floors and sometimes watch active lava. Mount Rainier and Crater Lake are stunning day trips. Lassen Volcanic National Park has hydrothermal areas you can hike to. Yellowstone's geysers are world-famous. Mount St. Helens' blast zone is open for hiking, and you can climb to the crater rim with a permit. In Alaska, tours fly over erupting Aleutian volcanoes.