Mud Volcano Area, Yellowstone National Park — Mud Pot, Dragon's Mouth Spring, and Acidic Hydrothermal Features

+2 more

Type

Mudpot/Hydrothermal Area

Accessibility

Drive-up view with boardwalks; lower loop wheelchair accessible; northern part paved but steep with stairs at the northern end.

Best Season

Spring through fall

Busiest Season

Summer (July–August)

Features

Mudpot, Sulfur Caldron, Dragon's Mouth Spring, fumaroles

Elevation

7,813 ft

Overview

About This Attraction

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.

Quick Facts

Type

Mudpot/Hydrothermal Area

Elevation

7,813 ft

Access

Drive-up view with boardwalks; lower loop wheelchair accessible; northern part paved but steep with stairs at the northern end.

Main Features

Mudpot, Sulfur Caldron, Dragon's Mouth Spring, fumaroles

What You'll See

Boardwalks and overlooks; bubbling mudpots, steaming vents, sulfur-stained rock, and Dragon's Mouth Spring adjacent to the road.

What Makes It Special

Located near the Yellowstone Caldera's resurgent dome; highly acidic hydrothermal chemistry; active mud production fueled by subterranean gases

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.

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

Visitor Tips

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.

Details

Location & Features

Type: Mudpot/Hydrothermal Area

Elevation: 7,813 ft

Distance from Entrance: 5.8 miles north of Fishing Bridge Junction; 9.7 miles south of Canyon Junction

GPS: Varies

What Makes It Unique:

Located near the Yellowstone Caldera's resurgent dome; highly acidic hydrothermal chemistry; active mud production fueled by subterranean gases

Geology

Formation Type: Mudpot/Hydrothermal Area

Scientific Interest:

Proximity to resurgent dome; ongoing ground deformation within the caldera; extremophile microbes in acidic waters

Getting There

Directions:

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.

Access Type: Drive-up view with boardwalks; lower loop wheelchair accessible; northern part paved but steep with stairs at the northern end.

Road: Paved trails with boardwalks; accessible routes along the lower loop

Seasonal Access: Spring, summer, and fall when the main park road is open.

Parking: Nearly 70 spots; can fill up, but openings occur as visits end.

Entry Fees: Varies; park entrance fees apply

Trails

Trailheads Here:

Mud Volcano Trailhead; Dragon's Mouth Spur

Connecting Trails:

Mud Volcano Loop; Dragon's Mouth Spur; Lower Loop

Photography & Viewing

Best Viewpoints:

Mud Volcano overlook; Sulfur Caldron overlook across the road; Dragon's Mouth Spring overlook

Photo Opportunities:

Steam plumes at dawn; close-up bubbling mud; sulfur-stained crusts with morning light

Best Photo Spots:

Overlooks for Mud Volcano and Sulfur Caldron; Dragon's Mouth Spring plumes

Sunrise/Sunset: Alpenglow possible; steam visible with sunrise

Stargazing: Moderate

Facilities

Restrooms (Vault toilets; accessible restrooms)
Interpretive Signs

Cell Service: Unreliable; expect patchy coverage

Wildlife & Nature

Common Wildlife:

Bison; elk; coyotes; grizzly bears; wolves

Best Wildlife Viewing: Bison commonly near boardwalks and parking; dawn and dusk for broader wildlife

Fall Colors Peak: Late September–October

Seasonal Information

Best Season: Spring through fall

Best Times: Early morning or late afternoon to avoid crowds; spring through fall for open roads

Road Opens: Spring through fall; check park alerts for closures

Busiest: Summer (July–August)

Parking Fills: Parking tends to fill in mornings during peak season; best to arrive before 9am

Snow Until: Lingering into spring; check park updates for snow conditions

Winter Access: Limited; most boardwalks not maintained for winter travel; road status varies

Weather:

Thermal area; sulfur odors; variable weather; can be windy near Hayden Valley

Nearby

Nearby Attractions:

Dragon's Mouth Spring; Sulfur Caldron; Hayden Valley; Fishing Bridge

Nearby Services:

Parking; vault toilets; interpretive signs; bring water

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

Visitor Information

Accessibility:

Lower loop wheelchair accessible; northern sections paved but steep; stairs at northern end

Family Friendly:

Boardwalks keep kids safe; be mindful of hot ground and sulfur vents

Nearby Facilities:

Parking lot; vault toilets; interpretive signs

Reviews

★★★★☆

4.7 /5

Based on 2066 Google reviews

Based on 2066 guest reviews

" 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."

Reviews from Google

Easy parking, easy boardwalk hike about two hours to finish the whole trail. Different shapes, colors and steam levels of geysers. The sulfur smell can be irritating for sensitive people, better wearing masks.

One of our first stops on our week long trip. The ranger was there to ensure no one went near the buffalo. Was very happy and excited to capture this moment. Highly recommend every family who is able to visit Yellowstone at least once.

This area was beyond fascinating! The immense amount of power being exerted throughout this hit spot was mind boggling. I honestly couldn't get over the fact that literally every pathway seemed to be lined with small and large mud pots alike, and the fumaroles were screeching against the hillside all the while. As we reached the peak of the hilltop, we witnessed a Bison taking a nap against one of the muddy pools, and then almost crossed paths with a small herd making their way down the hill towards the parking lot.

Showing 3 of 2066 reviews

FAQs

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?

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

Will I see bears or bison here?

Is there potable water nearby?

📖 nps.gov 📖 wikipedia.org 📖 yellowstone.org 📖 yellowstonenationalpark.com 📖 nationalparked.com 📖 hikespeak.com 📖 justgotravelstudios.com 📖 hikeramerica.com 📖 youtube.com 📖 wanderlog.com 📖 yellowstoneinsider.com 📖 10adventures.com ⭐ Google Reviews 📝 YourNPGuide Editorial

Information is compiled from official sources, verified traveler reviews, and editorial research. Learn how YourNPGuide works →

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Mud Volcano

Type

Accessibility

Best Season

Busiest Season

Features

Elevation

Overview

About This Attraction

Quick Facts

Main Features

What You'll See

What Makes It Special

Best Time to Visit

Safety Considerations

Visitor Tips

Details

Location & Features

Geology

Getting There

Trails

Photography & Viewing

Facilities

Wildlife & Nature

Seasonal Information

Nearby

Insider Tips

Visitor Information

Location

Address & Directions

Proximity

Reviews

The YNPG Verdict

Reviews from Google

FAQs

Mud Volcano

Type

Accessibility

Best Season

Busiest Season

Features

Elevation

Overview

About This Attraction

Quick Facts

Main Features

What You'll See

What Makes It Special

Best Time to Visit

Safety Considerations

Visitor Tips

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