How Many Active Volcanoes Are In The US?

The United States is home to one of the most volcanically active landscapes on Earth—ranking third globally behind Indonesia and Japan. So, how many active volcanoes are in the US? The answer might surprise you.

As of 2025, the United States has 161 potentially active volcanoes, with approximately 50 classified as "active" by the United States Geological Survey (USGS)—meaning they’ve erupted in the past 10,000 years and show signs of ongoing activity. These geological giants are more than just ticking time bombs; they’re fundamental forces that shape ecosystems, fuel scientific research, and even draw curious travelers.

Take a look at where these volcanoes are, what makes them active, and the specific peaks that continue to smolder, hiss, and remind us of the raw power beneath our feet.

What Is An Active Volcano?

The term “active” can be misleading. In volcanology, it doesn’t necessarily mean the volcano is erupting right now. A volcano is considered active if it has erupted within the Holocene Epoch (the last 10,000 years) and shows signs of current or potential unrest—such as earthquakes, gas emissions, or ground deformation.

Volcanoes that haven’t erupted for thousands of years but are not considered extinct fall into the “dormant” category, while extinct volcanoes are those that geologists believe will never erupt again.

So when we say the US has around 50 active volcanoes, we mean they have the potential to erupt and are monitored accordingly.

Active volcanoes in the United States are not limited to one region. However, they are heavily concentrated along the Pacific Ring of Fire, a geologically volatile arc that spans the Pacific Ocean. The vast majority are in Alaska, with notable concentrations in Hawaii, the Pacific Northwest, and parts of California and the Southwest.

Explore the key volcanic regions in more detail.

Alaska: America’s Volcanic Frontier

With over 130 volcanoes, Alaska is home to the largest number of active volcanoes in the US More than 50 have erupted in the past 300 years, and around 30 are currently considered active.

These volcanoes are part of the Aleutian Arc, a 1,500-mile-long chain stretching from mainland Alaska to the tip of the Aleutian Islands.

Notable Active Volcanoes in Alaska:

• Mount Redoubt – Last erupted in 2009, spewing ash 50,000 feet into the air.

• Shishaldin Volcano – One of the most active, with minor eruptions as recently as 2023.

• Pavlof Volcano – Frequently active, with ash plumes disrupting flights.

Alaska’s volcanoes are remote, but their impacts can be far-reaching. Ash clouds from eruptions often threaten international air travel routes across the Arctic and North Pacific.

Hawaii: Home of Constant Eruption

When people think of volcanoes in the US, Hawaii often comes to mind first—and for good reason. The Big Island is home to some of the most visibly active volcanoes in the world.

Key Volcanoes in Hawaii:

• Kīlauea – One of the most active volcanoes on Earth, it erupted almost continuously from 1983 to 2018. It has since continued intermittent activity, including lava lake refilling and effusive eruptions.

• Mauna Loa – The world’s largest volcano by volume, Mauna Loa erupted most recently in 2022 after nearly four decades of dormancy.

• Mauna Kea – Dormant, but still classified as potentially active.

• Hualālai – Hasn’t erupted since 1801, but remains monitored.

Hawaii’s volcanic landscape is not just geologically active but also culturally significant. Native Hawaiian traditions honor Pele, the goddess of volcanoes, whose fiery breath is said to shape the islands themselves.

Pacific Northwest: The Cascades

The Cascade Range, stretching from Northern California to British Columbia, is one of the most studied volcanic regions in the world. These volcanoes are part of the Cascadia Subduction Zone, where the Juan de Fuca Plate dives beneath the North American Plate.

Active Volcanoes in the Cascades:

• Mount St. Helens (Washington) – The most active volcano in the contiguous US, infamous for its catastrophic 1980 eruption. It has erupted several times since and continues to show signs of activity.

• Mount Rainier (Washington) – While it hasn’t erupted in over 1,000 years, its glacial cover and proximity to Seattle make it one of the most dangerous volcanoes in the US.

• Mount Hood (Oregon) – Erupted last in the 1700s, but hydrothermal activity indicates it’s still alive.

• Lassen Peak (California) – Erupted from 1914 to 1921 and is still considered active.

• Mount Shasta (California) – Last erupted in 1786, but frequent seismic activity warrants close monitoring.

The Cascades are known for their stratovolcanoes, steep-sided giants capable of highly explosive eruptions.

California and the Southwest

Beyond the Cascades, several volcanoes in California and the American Southwest are under observation by the USGS.

Key Active Volcanic Regions:

• Long Valley Caldera (California) – A massive volcanic depression near Mammoth Lakes. While it hasn’t erupted in 600 years, ground uplift and swarms of earthquakes keep it under surveillance.

• Coso Volcanic Field (California) – A hotbed of geothermal energy production.

• Ubehebe Craters (Death Valley) – Erupted roughly 2,000 years ago. Still considered active.

Although eruptions in this region are rare, the potential consequences of a volcanic event—especially near densely populated Southern California—prompt continuous monitoring.

US Territories: Volcanoes Beyond the Mainland

Several US territories also sit on tectonically active zones.

Notable Volcanoes:

• Pagan and Anatahan (Northern Mariana Islands) – Both erupted within the last two decades.

• Mount Pagan – Remains under observation due to frequent ash emissions.

• Kick 'em Jenny (Caribbean Sea) – Though technically in the territory of Grenada, it's close to US maritime interests and is watched closely.

While far from the continental US, these volcanoes are still part of the U.S. geological monitoring network.

How Are Volcanoes Monitored?

The United States is one of the few countries with a sophisticated volcanic monitoring system. The U.S. Geological Survey (USGS) operates five regional observatories:

1. Alaska Volcano Observatory (AVO)

2. Hawaiian Volcano Observatory (HVO)

3. Cascades Volcano Observatory (CVO)

4. California Volcano Observatory (CalVO)

5. Yellowstone Volcano Observatory (YVO)

These observatories use a combination of seismographs, GPS sensors, satellite data, gas analyzers, and webcams to track changes in volcanic activity in near real-time.

In 2019, the USGS launched the National Volcano Early Warning System (NVEWS) to prioritize volcanoes that pose the greatest risk to lives, property, and air travel. Of the 161 potentially active volcanoes in the US, 18 are classified as “very high threat.”

The Most Dangerous Volcanoes in the US

Being active doesn't necessarily mean dangerous. The risk comes from a combination of eruption potential, nearby population, and possible hazards like lahars (volcanic mudflows), pyroclastic flows, and ash clouds.

The top five most dangerous volcanoes in the US, according to the USGS, include:

1. Mount Kīlauea (Hawaiʻi)

2. Mount St. Helens (Washington)

3. Mount Rainier (Washington)

4. Mount Shasta (California)

5. Mauna Loa (Hawaiʻi)

Mount Rainier is particularly concerning because of its proximity to Seattle and Tacoma—and the fact that its ice-covered slopes could unleash deadly lahars if the mountain erupts.

America’s Fiery Landscape Is Always in Motion

So, how many active volcanoes are in the US? The current count stands at around 50 officially classified as active, with 161 potentially active volcanoes overall. These geological wonders span from Alaska to Hawaii, from the Cascades to California’s hidden calderas, and even into distant US territories.

While eruptions are rare on human timescales, the US is far from geologically quiet. Scientists continue to study, monitor, and prepare for the day when one of these sleeping giants awakens—again.

For travelers, volcanoes represent both risk and reward—offering breathtaking views, geological wonders, and a powerful reminder of Earth’s raw and unpredictable nature.

Quick Summary: Volcano Facts at a Glance

• Total potentially active volcanoes in the US: 161

• Volcanoes considered "active": ~50

• State with the most active volcanoes: Alaska

• Most active volcano: Kīlauea (Hawaii)

• Most dangerous volcano (by risk): Mount Rainier (Washington)

FAQ

What’s the difference between active and dormant volcanoes? 

Active volcanoes have erupted in the past 10,000 years. Dormant volcanoes haven’t erupted recently but could erupt again.

Can a volcano erupt without warning? 

Sudden eruptions are rare. Most volcanoes give signs—earthquakes, gas emissions, and ground deformation—before erupting.

What is the largest volcano in the US?

Mauna Loa in Hawai‘i is the largest volcano by volume on Earth.

Is Yellowstone an active volcano? 

Yellowstone is considered a supervolcano and is classified as potentially active, but it has not erupted in 640,000 years.