Mud Volcano is a geothermal area in Yellowstone National Park, near Hayden Valley and north of Yellowstone Lake. A short loop of boardwalks and paths passes bubbling mud pots, steaming vents and the roaring Dragon’s Mouth Spring, where steam and gas escape from a cave. The features range from easy-to-reach stops to steeper sections on the hillside. Sulfur gives the area a strong rotten-egg smell, but the churning mud and shifting clouds of steam make this a distinctive stop on a drive through the park.
What you’ll see along the loop
A network of short paths and boardwalk sections leads past Mud Volcano and other active geothermal features. The ground bubbles and hisses, while steam rises from the pools and slopes. The loop is about 0.6 mile, with some parts climbing a hillside. Several features sit close to the route, so you can see the area without committing to a long hike.
Dragon’s Mouth Spring is one of the most distinctive stops. Steam and gas emerge from a cave with a low roar, giving the spring its name. Nearby, the muddy pools bubble and shift, their gray tones set apart from the brighter colors found at some of Yellowstone’s other thermal areas.
Why the mud is gray
The area’s ground contains clay and soil above chambers that release hydrogen sulfide. As the gas rises, it forms sulfuric acid, which breaks down the surrounding material into mud. Steam and other gases move through the pools, creating the bubbling and gurgling activity visible from the paths. Sulfur compounds also give the area its strong smell.
Mud Volcano is a name for the muddy, active features here, not a tall cone erupting mud today. The changing steam, sounds and pools give the area a different character from Yellowstone’s colorful hot springs and geyser basins.
Planning your stop
The short route makes Mud Volcano a practical break while driving between the Yellowstone Lake area and Hayden Valley. You can keep to the boardwalks for a brief look or spend longer pausing at individual features. There are both easier sections and steeper stretches, so take care on the path and choose your direction with the gradients in mind.
The sulfur smell is noticeable as soon as you approach and can be uncomfortable if you are sensitive to it. A mask may help. Arriving early can also make parking easier, before the area gets busier later in the day. Keep an eye out for bison around the trails, but give wildlife space.
Preguntas frecuentes
How long does it take to visit Mud Volcano?
Allow about 30 to 60 minutes for the roughly 0.6-mile loop and time to stop at the geothermal features.
What can you see at Mud Volcano?
The area has bubbling mud pots, steaming vents and Dragon’s Mouth Spring, where steam and gas come from a cave.
Does Mud Volcano smell strongly of sulfur?
Yes. The sulfur odor is strong; bring a mask if you are sensitive to it.
Is the Mud Volcano trail steep?
The route includes easy boardwalk sections as well as steeper parts of a hillside. Walking counter-clockwise may help if you are concerned about the gradients.
