Mammoth Terraces and Upper Terrace Loop

Route Description for Mammoth Terraces and Upper Terrace Loop

The Mammoth Terraces Upper Loop is an incredible insight into the geological wonder of Yellowstone National Park. This trail is popular and can get busy and crowded, especially in the summertime. We suggest heading out on this hike early in the morning to beat the crowds. This trail is mostly boardwalk; please stick to the boardwalk and do not venture off-trail. The area's geothermal activity is very dangerous, and an off-trail adventure could result in serious injury or death.

With the World’s best display of travertine deposits, it is no wonder that the Mammoth Terraces are a tourist hotspot. The dynamic geothermal and seismic activity in this area makes no two visits alike. The terraces are well known for their bright colors and changing appearance. Don’t forget the camera on this outing; the Mammoth terraces are truly otherworldly.

To hike the Upper Terrace Loop, begin at the Sepulcher Mountain Trailhead and follow the path south. Straight away, you will see Liberty Cap on your right and the Opal Pool on your left. Just past these features, the trail will split, hike a quick out and back to your right to see Pallette Spring and Devils Thumb before continuing along the main trail. At the next divide, take the path on your left and stick to your left at the next divide to follow the circuit clockwise. Make your way past the series of terraces and hot springs as you work your way south. 1.8 miles from the trailhead, the path will split; take the trail on your right to loop your way back up to the trailhead where you began.

Once you’ve completed your hike, check out the other sites in the Mammoth area, including the Albright Visitors Center and historic Fort Yellowstone, before heading on to the next adventure.

Trail Highlights

Opal Terrace

The Opal Terrace is one of the first sights on the Upper Terrace Loop Trail; this hot spring became active in 1926 and deposits up to 1 foot of travertine per year. The activity of the area infringes upon the historic cabin located next to the terrace that architect Robert Reimer built in 1907. The activity of the Opal Terrace has posed an interesting challenge for the National Park Service, who work hard to preserve both the natural and cultural history of the area.

Liberty Cap

The Liberty Cap is a prominent 37-foot tall tower of travertine that was formed by a now-extinct thermal feature. This feature was named after the peaked caps worn during the French Revolution that were symbols of freedom.

Canary Spring

The Canary Spring is a fickle hot spring that goes dormant for long periods. In the late 1800s, this spring was covered with bright yellow filamentous bacteria, hence the name. These days, the Canary Spring varies in color from soft orange, brown, and pink to bright neon.

Minerva Terrace

Named for the Roman goddess of artists and sculptors, this vibrant terrace is the site of dramatic shifts in geothermal activity. This terrace can be found either bone-dry or highly active. This is one of the most colorful terraces in the area and is a major tourist attraction.

Frequently Asked Questions

What are the formations at Mammoth Hot Springs made of?

The Mammoth Terraces are made of travertine (calcium carbonate) deposited by the hot springs in the area.

How hot is the water at Mammoth Hot Springs?

The water at Mammoth Hot Springs is approximately 164 degrees fahrenheit (73 degrees Celsius).