In the northern part of the park visitors can visit the Mud Volcano region. This area is close to the centre of the caldera and includes lots of unique geothermal features. The whole area has a specific smell of rotten egg, which occurs due to the evaporating gases.
This region is more acidic than any other part of the park. This acid destroys the rocks and turns them into mud. Some of the most striking mud pots are located a few kilometers from below the Fishing Bridge. Long ago the Mud Volcano erupted with 9 m high splashes that easily covered the trees. The volcano has the temperature of 87.5°C and is around 5 m deep. Nowadays it is more like a crater with boiling mud inside. But, who knows when it will wake up again with massive mud streaming upwards.
Yellowstone Mud Volcano area is accessible during the summer and autumn months.
Practical info
When is the best time to visit Mud Volcano region?
To enjoy better accessibility and weather, it is best to visit Mud Volcano region during the summer and autumn months (May-October). Visitors can avoid crowds by going in May/June or after Labor Day until mid-October. Show more
Why does the region have a smell of rotten egg?
The Mud Volcano region has a characteristic smell of rotten egg, owing to the presence of hydrogen sulfide gas. This gas is produced by bacteria decomposing organic matter in the soil. Visitors should know that inhalation of this gas in high concentrations can be hazardous. Show more
What causes the acid in the Mud Volcano region?
In the Mud Volcano region, the release of sulfuric acid from hydrothermal activity dissolves rocks and minerals, turning them into mud. The highly acidic environment fosters the growth of microorganisms called extreme thermophiles, which survive in environments such as boiling mud pots and acidic pools. Show more
Where are the most striking mud pots located?
Located below Fishing Bridge, a few kilometers away, visitors can observe some of the Mud Volcano region's remarkable mud pots. Surrounded by boardwalks, these mud pots hold boiling mud with clay, silica, and gas bubbles. Visitors are reminded not to wander off the boardwalks as the apparently thin crust is unreliable and could lead to severe injury. Show more
How deep is the Mud Volcano and what is its current state?
Although Mud Volcano was an active volcano before, it is now dormant. The volcano's crater is around 5 meters deep, holding boiling mud that produces loud bubbling sounds. Compared to the past's high blasting eruptions, the volcano's eruptions are now slow and gurgling. Although visitors can observe the Mud Volcano spectacular geothermal features, they should follow safety precautions and stay on designated trails. Show more
