Mud Volcano Trail
What to Expect
Safety Advisory
Stay on the boardwalk at all times — the ground around hydrothermal features is a brittle crust over boiling, acidic water. People have died stepping off trail in areas exactly like this. The danger is invisible and there are no second chances.
The sulfur fumes can be intense, particularly at Mud Volcano and Black Dragon's Caldron. If you have asthma or respiratory issues, carry your inhaler and be prepared to move quickly past the most concentrated vents.
Bison frequently graze in the meadows around the parking area and occasionally wander onto the boardwalk itself. Give them at least 25 yards of space — they are faster than you and profoundly unimpressed by your schedule.
Trail Details
Pro Tips
Hit this trail before 9 AM or after 5 PM — the parking lot is small and sits right on the Grand Loop Road between Canyon and Fishing Bridge, so midday traffic turns it into a bottleneck. Early morning also means the steam is thicker and more photogenic against cool air.
Walk the loop counterclockwise (uphill first) to tackle the steepest section while you're fresh and finish on the flat boardwalk past Dragon's Mouth Spring — it's a better narrative arc for the experience.
Bring a lens cloth or microfiber towel. The sulfuric mist coats camera lenses and phone screens fast, especially at Dragon's Mouth Spring where the steam blows directly across the boardwalk. Shooting from the upwind side of each feature makes a real difference.
Photos
NPS / Addy Falgoust
