Old Faithful Geyser Eruption in Yellowstone National Park at Sunset

The 5 Largest Geysers in the US

From the eerie hiss of steam vents to the thundering eruption of boiling water into the sky, geysers are among the most dramatic and mesmerizing natural features in America. These geothermal wonders draw travelers from across the globe, especially to the steaming basins of Yellowstone National Park, where most of the world's geysers reside. While many are small or unpredictable, a handful rise above the rest—literally.

Explore the five largest geysers in the United States, focusing on their eruption heights, frequency, and what makes each one a bucket-list experience.

Steamboat Geyser – Yellowstone National Park, Wyoming

Two tourists camp out with chairs, waiting for the Steamboat Geyser to erupt. Editorial credit: melissamn / Shutterstock.com

Claim to fame: Tallest active geyser in the world

Maximum eruption height: Up to 300 feet

Eruption duration: 3 to 40 minutes

Eruption interval: Irregular, from days to years

Location: Norris Geyser Basin

Yellowstone’s Steamboat Geyser is not only the largest in the United States, but also holds the title of the tallest currently active geyser on Earth. When it erupts, Steamboat shoots superheated water up to 300 feet in the air, creating a roaring column of mist and spray that dwarfs nearby trees.

However, witnessing a Steamboat eruption is no small feat. The geyser is famously unpredictable, with intervals between major eruptions ranging from 3 days to several years. In 2018, it entered a particularly active phase, erupting dozens of times over a single year, but this level of activity fluctuates without warning.

Even when it’s not erupting, Steamboat offers a visual spectacle. Its minor eruptions—reaching up to 40 feet—occur more regularly and are accompanied by dramatic steam emissions that rumble through the Norris Geyser Basin.

Old Faithful – Yellowstone National Park, Wyoming

The most famous Old Faithful geyser eruption at Yellowstone National Park. Editorial credit: Eniko Balogh / Shutterstock.com

Claim to fame: Most famous geyser in the world

Maximum eruption height: 90 to 184 feet

Eruption duration: 1.5 to 5 minutes

Eruption interval: Roughly every 90 minutes

Location: Upper Geyser Basin

No list of America’s geysers would be complete without Old Faithful. While it’s not the tallest, its fame comes from one key trait: reliability. Old Faithful erupts about every 35 to 120 minutes, making it the most predictable large geyser in Yellowstone. Eruption heights typically range between 90 and 184 feet, with an average duration of about 3.5 minutes.

Its consistency, along with its central location near the Old Faithful Visitor Education Center and a large network of boardwalks, makes it the most viewed geyser on the planet. Park rangers and apps even post updated predictions, allowing visitors to time their arrival to catch the next eruption.

Old Faithful is part of the larger Upper Geyser Basin, home to more than 150 geysers, making it one of the highest-concentration geyser fields in the world.

Giant Geyser – Yellowstone National Park, Wyoming

Claim to fame: One of Yellowstone’s tallest geysers when active

Maximum eruption height: Up to 250 feet

Eruption duration: More than an hour

Eruption interval: Unpredictable, often years apart

Location: Upper Geyser Basin

Tucked away in the Upper Geyser Basin near the Firehole River, Giant Geyser lives up to its name—when it decides to erupt. Its explosive displays can reach 250 feet high and last for over an hour, making it one of the most powerful and sustained geysers in the world.

However, Giant Geyser is notoriously temperamental. It has experienced long dormant periods, sometimes lasting over a decade. During active phases, eruptions might occur every few days or weeks, but there are no guarantees.

Despite its unpredictability, the site is well worth visiting. When Giant Geyser is in a pre-eruption phase, it bubbles and boils dramatically, creating a sense of anticipation that grips onlookers.

Great Fountain Geyser – Yellowstone National Park, Wyoming

Great Fountain Geyser erupting, in the Lower Geyser Basin of Yellowstone National Park.

Claim to fame: Most scenic and photogenic large geyser

Maximum eruption height: 100 to 200 feet

Eruption duration: 40 to 60 minutes

Eruption interval: 10 to 14 hours

Location: Firehole Lake Drive, Lower Geyser Basin

Great Fountain Geyser is not only among the largest geysers in the US, but also one of the most beautiful. Nestled along the scenic Firehole Lake Drive, it erupts in a tiered, fountain-like display that can rise to over 200 feet, framed by terraced pools that glow in the sunlight.

Eruptions typically last close to an hour and occur every 10 to 14 hours, making them somewhat predictable with ranger-posted estimates available at nearby visitor centers. Photographers often stake out the area at sunset, when the geyser’s reflection in its multicolored runoff pools creates a stunning visual.

Unlike cone geysers such as Old Faithful, Great Fountain is a fountain geyser, which means it erupts from a pool of water rather than a narrow vent. This allows for a wide, dramatic spray.

Castle Geyser – Yellowstone National Park, Wyoming

Castle Geyser erupts with hot water and steam with pools of thermophilic bacteria.

Claim to fame: Oldest cone geyser in Yellowstone

Maximum eruption height: Up to 75 feet

Eruption duration: 20 minutes of water, followed by 30-40 minutes of steam

Eruption interval: on average, every 14 hours

Location: Upper Geyser Basin

Castle Geyser combines historic grandeur with a spectacular eruption sequence. Named for its castle-like mineral cone, the geyser is estimated to be thousands of years old, making it one of the oldest active geysers in Yellowstone.

Castle erupts roughly every 14 hours, shooting water up to 75 feet into the air for about 20 minutes, followed by a dramatic steam phase that can last up to 40 minutes. Its deep rumbling and wide steam plumes give it an imposing presence, even among Yellowstone’s heavy hitters.

Thanks to its predictable cycle, many visitors plan their walks around the Upper Geyser Basin trail loop to coincide with a Castle eruption.

Honorable Mentions

Riverside Geyser

Height: Up to 75 feet
Unique Feature: Arches over the Firehole River
Predictable: Yes, every 5.5–7 hours

Grand Geyser

Height: Up to 200 feet
Predictable: Every 7–15 hours
Duration: 9 to 12 minutes

These geysers nearly made the top five and are also located in Yellowstone. They offer their own blend of beauty and consistency and are easily viewed via boardwalks in the Upper Geyser Basin.

What Makes a Geyser “Large”?

Grand Prismatic Pool at Yellowstone National Park.

When classifying geysers by size, several factors come into play:

Eruption height: The maximum vertical reach of the water column.
Eruption duration: How long the geyser stays active once it begins.
Eruption volume: The total amount of water expelled (harder to measure).
Frequency and predictability: While less about size, frequency determines visitor accessibility.

By these metrics, the geysers listed above stand out as the largest and most significant in the United States—and the world.

Planning Your Visit

Tourists watching the Old Faithful erupting in Yellowstone National Park.

If you’re traveling to see these geysers, especially in Yellowstone, keep these tips in mind:

Stay informed: Check the Yellowstone National Park geyser prediction schedule, available online and at visitor centers.
Be patient: Some geysers, like Steamboat or Giant, are highly irregular. Others like Old Faithful are reliably on time.
Pack smart: Bring water, layers, and sunscreen—geothermal areas can be surprisingly exposed and dry.
Use boardwalks: Stay on marked paths. The ground near geysers is thin and dangerous.
Photograph wisely: Early morning and late evening light create dramatic conditions, especially for colorful pools and steam plumes.