Hot springs have long captivated people with their soothing waters, natural beauty, and geothermal intrigue.  These geothermal wonders, where underground water is heated by the Earth’s internal heat, range from tranquil pools to massive springs bubbling with energy.  Across the United States, the largest hot springs are both geological marvels and cultural landmarks, offering insights into nature’s power and healing properties.  Here are the top 10 largest hot springs in the United States, ranked by size, and their fascinating stories.

#1: Grand Prismatic Spring – 370 Feet Wide

Located in Yellowstone National Park, Wyoming, Grand Prismatic Spring is the largest hot spring in the United States and the third largest in the world.  With a diameter of 370 feet and a depth of over 120 feet, its vivid rainbow-colored rings—created by heat-loving microbes—make it an iconic sight.  Discharging thousands of gallons of water daily, the spring’s temperature hovers around 160°F.  Indigenous tribes revered it for its mystical appearance, and early explorers described it as a surreal, steaming cauldron.  Today, it’s a centerpiece of Yellowstone’s geothermal attractions.

#2: Excelsior Geyser Crater – 300 Feet Wide

Also located in Yellowstone National Park, Excelsior Geyser Crater is a massive hot spring measuring 300 feet across.  Once an active geyser, it now serves as a superheated pool, discharging over 4,000 gallons of water per minute into the Firehole River.  The steaming waters, surrounded by rocky terraces, create a dramatic landscape.  Historical accounts from the late 19th century describe its powerful eruptions that reached heights of 300 feet before it transitioned into a spring.

#3: Mammoth Hot Springs – Terraces Over 1.5 Miles Long

Mammoth Hot Springs in Yellowstone is a complex system of travertine terraces spanning over 1.5 miles.  These cascading formations are created by calcium carbonate deposits from the hot spring water.  The terraces change constantly, with some areas becoming dormant and others newly active.  Indigenous tribes used the springs for ceremonial purposes, and early settlers marveled at their unique beauty.

#4: Hot Springs State Park – 3.6 Million Gallons Per Day

Located in Thermopolis, Wyoming, Hot Springs State Park features one of the largest hot springs in the country, discharging 3.6 million gallons of water daily.  The water emerges at a soothing 135°F and is channeled into soaking pools.  The spring has been a sacred site for Native American tribes for centuries, and the park now blends recreation with history, offering trails and cultural exhibits.

#5: Boiling River – 140°F Waters

The Boiling River in Yellowstone National Park is where a hot spring meets the Gardner River, creating a natural hot tub effect.  The water temperature can reach up to 140°F, cooling to comfortable levels as it mixes with the river.  Visitors flock to this unique spot to soak in the geothermal warmth amidst stunning scenery.  The Boiling River has long been a favorite for adventurers seeking a natural spa experience.

#6: Glenwood Hot Springs – Largest Mineral Hot Spring Pool

Glenwood Hot Springs in Colorado boasts the world’s largest mineral hot spring pool, measuring over 400 feet long.  Fed by the Yampah Spring, the pool’s water temperature ranges from 90°F to 104°F.  The Ute tribe historically used the spring for its healing properties, and today it is a luxurious retreat.  The area’s rich history includes its use as a health resort in the late 19th century.

#7: Warm Springs – 1,000 Gallons Per Minute

Located in Warm Springs, Georgia, this spring discharges 1,000 gallons of mineral-rich water per minute at a constant 88°F.  Made famous by President Franklin D. Roosevelt, who sought relief from polio in its waters, the spring is now part of the Roosevelt Warm Springs Institute.  The site is steeped in historical significance and continues to draw visitors for its therapeutic qualities.

#8: Pagosa Springs – 144°F Waters

Pagosa Springs in Colorado is home to the deepest geothermal hot spring in the world, as certified by the Guinness Book of World Records.  The spring’s surface temperature reaches 144°F, feeding a series of soaking pools along the San Juan River.  The area’s name, derived from the Ute word “Pagosah,” means “healing waters.”  Its mineral-rich waters have drawn visitors for centuries.

#9: Ojo Caliente – Multiple Mineral Springs

Ojo Caliente Mineral Springs in New Mexico is one of the oldest natural health resorts in the United States, offering multiple hot springs with unique mineral compositions, including iron, soda, and arsenic.  The water temperatures range from 80°F to 109°F.  Indigenous peoples believed the waters had spiritual and healing powers, and the resort maintains a tranquil atmosphere to honor its heritage.

#10: Strawberry Park Hot Springs – Rustic Serenity

Strawberry Park Hot Springs in Colorado offers a rustic retreat with pools fed by naturally heated water.  The springs’ temperature varies between 101°F and 106°F, surrounded by scenic forests and mountains.  The site blends natural beauty with relaxation, creating a serene escape for visitors.  Stories of settlers discovering the springs add a touch of historical charm to this beloved destination.

The largest hot springs in the United States are not just geological marvels but also cultural treasures, offering relaxation, healing, and a connection to nature’s power.  From the vibrant colors of Grand Prismatic Spring to the soothing waters of Glenwood Hot Springs, these geothermal wonders highlight the diversity and beauty of the American landscape.  They continue to captivate visitors and stand as reminders of the Earth’s incredible energy and life-giving properties.