Mud Volcano

Steam swirls above bubbling mud at Mud Volcano, Yellowstone’s hydrothermal field.

Insider tip

Arrive before 9am or after 3:30pm to beat crowds

Insider tip

Keep to the boardwalk; ground is hot and chemically aggressive

The light

Alpenglow possible; steam visible with sunrise

Heads up

Chemistry: highly acidic waters and toxic gases; Temperature: surface ground can exceed 200°F; Gravity: uneven boardwalks; Wildlife: keep distance from large m…

Natural Attraction

Natural AttractionOPERATIONAL★ 4.7
Mudpot/Hydrothermal Area7,813 ftRestrooms availableNo permit neededGolden-hour pick

Mud boils and steam hiss along the boardwalk. Sulfur Caldron and Dragon's Mouth Spring vent steam and mud, while the air carries a rotten-egg scent. This hydrothermal patch sits in the Yellowstone Caldera near a resurgent dome—ground deformation is ongoing. Magma heats groundwater, creating acidic chemistry that dissolves rock into the clay-rich mud that churns beneath pressure.

Getting there & parking

How To Get There
From Grand Loop Road, turn into the Mud Volcano parking area on the west side; follow boardwalks to Mud Volcano, Sulfur Caldron, and Dragon's Mouth Spring.
Distance From Entrance
5.8 miles north of Fishing Bridge Junction; 9.7 miles south of Canyon Junction
Road Type
Paved trails with boardwalks; accessible routes along the lower loop
Parking Availability
Nearly 70 spots; can fill up, but openings occur as visits end.
Peak Fill Times
Parking tends to fill in mornings during peak season; best to arrive before 9am
GPS Coordinates
Varies

When to go

Best Time To Visit
Spring through fall when the main park road is open. Morning light highlights the steam and mud; avoid midday glare. To dodge crowds in peak summer, arrive before 9am or after 3:30pm.
Best Visit Times
Early morning or late afternoon to avoid crowds; spring through fall for open roads
Sunrise Sunset Quality
Alpenglow possible; steam visible with sunrise
Best Season
Spring through fall
Busiest Season
Summer (July–August)
Seasonal Access
Spring, summer, and fall when the main park road is open.
Road Opening Dates
Spring through fall; check park alerts for closures
Snow Lingering
Lingering into spring; check park updates for snow conditions
Winter Access
Limited; most boardwalks not maintained for winter travel; road status varies
Weather Patterns
Thermal area; sulfur odors; variable weather; can be windy near Hayden Valley
Fall Colors Peak
Late September–October

What you will experience

Attraction Type
Mudpot/Hydrothermal Area
Main Features
Mudpot, Sulfur Caldron, Dragon's Mouth Spring, fumaroles
What Youll See
Boardwalks and overlooks; bubbling mudpots, steaming vents, sulfur-stained rock, and Dragon's Mouth Spring adjacent to the road.
Unique Characteristics
Located near the Yellowstone Caldera's resurgent dome; highly acidic hydrothermal chemistry; active mud production fueled by subterranean gases
Photo Opportunities
Steam plumes at dawn; close-up bubbling mud; sulfur-stained crusts with morning light
Photography Spots
Overlooks for Mud Volcano and Sulfur Caldron; Dragon's Mouth Spring plumes
Best Viewpoints
Mud Volcano overlook; Sulfur Caldron overlook across the road; Dragon's Mouth Spring overlook
Common Wildlife
Bison; elk; coyotes; grizzly bears; wolves
Best Wildlife Times
Bison commonly near boardwalks and parking; dawn and dusk for broader wildlife
Geological Formation Type
Mudpot/Hydrothermal Area
Scientific Interest
Proximity to resurgent dome; ongoing ground deformation within the caldera; extremophile microbes in acidic waters
Stargazing Quality
Moderate

Facilities, fees & access

Entry Fees
Varies; park entrance fees apply
Permits Required
No
Restrooms Available
Yes
Restroom Type
Vault toilets; accessible restrooms
Picnic Areas
No
Water Available
No
Cell Service
Unreliable; expect patchy coverage
Interpretive Signs
Yes
Accessibility
Lower loop wheelchair accessible; northern sections paved but steep; stairs at northern end
Accessibility Level
Drive-up view with boardwalks; lower loop wheelchair accessible; northern part paved but steep with stairs at the northern end.
Nearby Services
Parking; vault toilets; interpretive signs; bring water
Nearby Facilities
Parking lot; vault toilets; interpretive signs
Family Friendly Notes
Boardwalks keep kids safe; be mindful of hot ground and sulfur vents

Safety

Safety Considerations
Chemistry: highly acidic waters and toxic gases; Temperature: surface ground can exceed 200°F; Gravity: uneven boardwalks; Wildlife: keep distance from large mammals; Do not leave the boardwalk

Nearby

Nearby Attractions
Dragon's Mouth Spring; Sulfur Caldron; Hayden Valley; Fishing Bridge
Connecting Trails
Mud Volcano Loop; Dragon's Mouth Spur; Lower Loop
Trailheads Here
Mud Volcano Trailhead; Dragon's Mouth Spur

Planning advice

Insider Tips
  • Arrive before 9am or after 3:30pm to beat crowds
  • Keep to the boardwalk; ground is hot and chemically aggressive
  • Bison are common—give space; carry bear spray if venturing beyond the boardwalk
  • Dragon's Mouth Spring is accessible via a short spur; the sulfur smell can be strong
  • Dawn and dusk offer dramatic lighting and wildlife activity
Tips Advice
  • Stay on the boardwalks at all times; the ground is hot and chemically aggressive.
  • Carry water; no potable water spigots are noted here.
  • Bison are common—keep 25 yards from all wildlife, 100 yards from bears and wolves.
  • The sulfur smell can irritate sensitive visitors; masks help.
  • Bear spray advisable when moving beyond the immediate boardwalk zones; cell service is unreliable.

More details

Park Area
Hayden Valley
Elevation Feet
7813
Visitor Center Present
No
Guided Tours Available
No
Fishing Nearby
No
Swimming Allowed
No
Boating Allowed
No
Climbing Areas
No
Review Summary
Mud Volcano presents a dynamic, close-up look at Yellowstone's geothermal system. The boardwalks provide safe access to bubbling mud and steam, while the sulfur air and heat remind you of the park's volcanic heart. Parking can be competitive in peak season, so plan timing accordingly.

Location

Dragon's Mouth Spring at Mud Volcano in Yellowstone National Park, a wooden sign set on sandy ground with pines and blue sky.Mud Volcano at Yellowstone National Park emits steam over vivid mineral pools and muddy terrain.Mud Volcano pool at Yellowstone National Park showing a steaming blue-green pool surrounded by mineral terraces and grasses under a clear sky.Mud Volcano information panel at Yellowstone National Park explains steaming mud pools and explosive terrain in the Mud Volcano area.

Frequently asked questions

Do I really need to arrive before 9am to get parking?

Yes. The Mud Volcano lot holds ~70 spots and fills quickly in peak season; arriving before 9am or after 3:30pm helps secure a space.

Is it worth the 0.6–0.85 mile loop to see Mud Volcano and Dragon's Mouth Spring?

Yes. The short loop exposes bubbling mudpots, steaming vents, and the dramatic Dragon's Mouth Spring; the boardwalks keep you safe while you observe the chemistry in action.

Can I walk off the boardwalk to get closer to the mud?

No. Leaving the boardwalk endangers you and damages the delicate hydrothermal ground; stay on the designated paths.

Will I see bears or bison here?

Bison are common around Mud Volcano; maintain 25 yards from all wildlife, and 100 yards from bears and wolves.

Is there potable water nearby?

Potable water spigots aren’t noted at Mud Volcano; bring water from elsewhere in the park.

Grand Prismatic Spring

Rainbow rim of a hot spring; colors arise from thermophiles in Yellowstone's volcanic system.

Yellowstone Lake

Caldera lake tilted by resurgent domes; hydrothermal vents dot the lakebed.

Lake Butte Overlook

Panoramic view of Yellowstone Lake from the caldera rim; distant Tetons on clear days.

Artist Point

Lower Falls overlook; canyon walls colored by hydrothermal alteration of rhyolite.

Gibbon River

84 ft Gibbon Falls; river through hydrothermal basins along Grand Loop Road.

Gibbon Falls

84-foot cascade over an ancient Yellowstone lava flow; drive-up overlook with a wheelchair-friendly path.

Sources

Editorial review: YourNPGuide Editorial Team. Information is compiled from official sources, verified traveler reviews, and editorial research; no firsthand visit is implied unless explicitly documented. Learn how YourNPGuide works.

Last updated January 2026. Report an issue.