Dragon's Mouth Spring

Dragon’s Mouth Spring is one of Yellowstone National Park’s most mesmerizing and dramatic geothermal features, located in the Mud Volcano area near Hayden Valley. This powerful hot spring immediately captures attention with its deep, echoing roars and steaming, cave-like mouth that gives the illusion of a dragon breathing from beneath the earth. 

As visitors approach, they can hear gurgling, rumbling, and splashing sounds coming from within the dark opening, accompanied by bursts of steam that shoot rhythmically from the vent. The combination of sound, sight, and smell makes Dragon’s Mouth Spring one of the most sensory and memorable experiences in the park.

Dragon's Mouth Spring

Quick Reference: Dragon’s Mouth Spring

Category	Details
Name	Dragon’s Mouth Spring
Location	Mud Volcano Area, near Hayden Valley, Yellowstone National Park, Wyoming, USA
Feature Type	Hot Spring / Fumarole Hybrid
Geological Basin	Mud Volcano Hydrothermal Area
Water Temperature	Approximately 180°F–195°F (82°C–90°C)
pH Level	Acidic (typically around 2–3)
Color Description	Murky green-gray due to suspended minerals and clays
Distinctive Features	Cave-like opening emitting steam, water splashes, and roaring sounds resembling a “dragon’s breath”
Name Origin	Named for its roaring sound and steam bursts that appear like a dragon breathing from

The spring’s name perfectly matches its appearance and behavior. In the early days of Yellowstone’s exploration, visitors described it as a dragon hiding in the hillside, its “mouth” releasing bursts of boiling water and steam with growling vibrations that shook the ground. The feature was officially named “Dragon’s Mouth Spring” for this reason, and the name has endured for over a century. The cave-like vent continuously churns with superheated water and steam, creating a natural amphitheater of geothermal energy. The sound results from gases exploding through the vent’s narrow opening, while the movement of water in and out of the chamber creates the illusion of breathing.

Geologically, Dragon’s Mouth Spring is a hot spring venting from a fissure connected to a network of hydrothermal channels deep underground. The water within the pool is highly acidic, enriched with hydrogen sulfide gas, which gives off a distinct sulfur smell often compared to “rotten eggs.” The average temperature hovers near boiling, around 180°F–195°F (82°C–90°C), depending on seasonal variations and hydrothermal pressure. The water’s murky greenish-gray color comes from suspended clay and minerals brought to the surface from deep underground reactions between hot water, volcanic rock, and gases.

What makes Dragon’s Mouth Spring particularly fascinating is its dynamic nature. Unlike most hot springs that remain calm, this one constantly churns, spits, and pulses. These fluctuations reflect changes in pressure below the surface — a reminder that Yellowstone’s volcanic system remains very much alive. Over the years, its intensity has varied, sometimes producing stronger roars or more forceful splashes, though it remains one of the safest-to-view active springs in the area thanks to the elevated boardwalks.

Surrounded by lush forests and the rolling hills of Hayden Valley, Dragon’s Mouth Spring offers a dramatic contrast between the serenity of nature and the raw power of geothermal energy. The Mud Volcano area, where it resides, is among the most thermally active zones in Yellowstone, featuring other remarkable features such as Mud Volcano itself and the Sour Lake area nearby. Each emits different gases and minerals, creating a diverse landscape of bubbling mud pots, fumaroles, and hot springs.

Visitors to Dragon’s Mouth Spring are often captivated not just by the visual spectacle but also by the sound — a deep, primal rumbling that feels as though the earth itself is alive. The spring embodies the mysterious and untamed spirit of Yellowstone, serving as a reminder that beneath the park’s beautiful surface lies one of the most powerful geothermal systems on the planet. It’s an experience that engages every sense — the sight of steam and color, the smell of sulfur, the heat rising from the earth, and the unmistakable sound of Yellowstone’s “dragon” breathing in the heart of its volcanic world.