Members of the 1870 Washburn Expedition named Mud Volcano for the cone shaped mud that covered the feature when they first saw it. By 1872, a thermal explosion had blown the cone away to reveal the feature we see today. While Mud Volcano is a single feature, the entire region is known as the Mud Volcano Area.

The acidity of this area is the driving factor in the formation of mudpots, as well as the rotten egg smell. The hydrogen sulfide gas that is abundant here supplies energy for microorganisms. These microbes help convert that gas into sulfuric acid that breaks down rock into mud.

The bubbling action is the release of gases. Hydrogen sulfide, steam, carbon dioxide and other gases explode through layers of mud as they make their way to the surface.

The trail around the basin is 2/3 of a mile long. It’s best to start at Mud Caldron and walk the basin clockwise.

Dragon’s Mouth Spring, which has had at least 17 different names, is a feature you won’t want to miss. In 1913, a tourist tacked a note to a tree changing the name from Green Gable Spring to Dragon’s Mouth Spring.
 
Just across the street from the parking lot, you find Sulphur Caldron. With a ph of between 1 and 2, Sulphur Caldron is one of the most acidic springs in Yellowstone. It is about as acidic as battery acid.  

While the acidity and heat of these features pose a threat, they are not the only dangers here. Bison and grizzly bears frequent this area. Automobile traffic also poses a threat here. Use extreme caution when crossing the road, especially with young ones.

The Mud Volcano area sits atop one of Yellowstone’s resurgent domes. Researchers monitor this area for clues to future volcanic activity. The beautiful, yet strange Mud Volcano area may someday give us the clues that we need to understand past volcanism and predict the future.