Green Dragon Spring

Green Dragon Spring, located in the Back Basin of Norris Geyser Basin in Yellowstone National Park, is one of the most captivating and mysterious thermal features in the park. True to its name, this spring evokes an almost mythical image — a steaming, sulfurous pool with a vivid green hue and thick mineral-lined walls that resemble the lair of a dragon. The combination of color, sound, and constant thermal activity makes Green Dragon Spring a mesmerizing example of Yellowstone’s dynamic geothermal power.

Green Dragon Spring

Quick Reference: Green Dragon Spring

Attribute	Details
Name	Green Dragon Spring
Location	Back Basin, Norris Geyser Basin, Yellowstone National Park, Wyoming, USA
Type	Hot Spring
Geothermal Area	Part of the Norris Geyser Basin, the hottest and most changeable geothermal region in Yellowstone
Color	Deep green hue caused by blue water mixing with yellow sulfur deposits
Average Temperature	Extremely hot, typically near the boiling point (around 199°F / 93°C)
pH Level	Acidic due to sulfuric gases; estimated around 2–3
Depth	Unknown, vent extends into underground channels
Main Characteristics	Emits hydrogen sulfide gas, producing strong sulfur odor; frequent bubbling and hissing sounds
Origin of Name	Named for its vivid color and the “growling” sounds resembling a dragon’s lair
Geological Composition	Rich in sulfur and mineral crusts formed from hydrothermal alteration
Microbial Life	Contains thermophilic microorganisms adapted to high heat and acidity
Notable Sounds	Bubbling, hissing, and rumbling from gas release within the vent
Accessibility	Easily viewed from the Back Basin boardwalk trail at Norris Geyser Basin
Nearby Features	Steamboat Geyser, Echinus Geyser, and Porkchop Geyser
Safety Note	Stay on boardwalks; ground near the spring is unstable and can cause severe burns
Fun Fact	The combination of color, steam, and sound creates the illusion of a mythical creature hidden beneath the surface

The spring’s green color comes from a blend of factors, including the reflection of sunlight off its hot, clear blue water and the presence of yellow sulfur deposits that coat the vent and surrounding rocks. This interplay of color gives the water a greenish tint that seems to glow from within, especially under direct sunlight. The spring constantly emits steam and hydrogen sulfide gas, which produces the distinct “rotten egg” odor characteristic of sulfur springs. These gases rise from deep underground, where superheated water interacts with volcanic gases and minerals before venting through the surface pool.

Green Dragon Spring also has an audible presence — visitors often hear bubbling and hissing sounds echoing from within its vent. The gases escaping from the spring create rhythmic bursts and growling tones that inspired the “dragon” in its name. The feature lies within Norris Geyser Basin, the hottest and most changeable geothermal area in Yellowstone, where subsurface activity frequently shifts the appearance and temperature of springs and geysers. Green Dragon Spring’s activity, color intensity, and water level can all vary depending on changes in underground pressure and heat flow.

The Back Basin, where Green Dragon Spring is located, is a more forested and atmospheric section of Norris Geyser Basin, contrasting with the open, stark landscape of the nearby Porcelain Basin. The boardwalk trail winds past numerous geothermal features, but few are as visually and aurally striking as Green Dragon Spring. The pool’s vibrant colors, combined with the billowing steam that rises from its vent, create an otherworldly scene that fascinates visitors and photographers alike.

In many ways, Green Dragon Spring represents the raw, living character of Yellowstone’s geothermal system — vibrant, unpredictable, and full of wonder. Standing before it, with its green depths steaming and hissing like a creature from legend, visitors get a rare glimpse into the power and beauty that define the park’s volcanic heart.