Mammoth Hot Springs
Mammoth Hot Springs is a huge area of travertine terraces and springs accessed by a large network of boardwalks. To reach the area, drive 0.6 miles south of Mammoth Junction, or 20.8 miles north of Norris Junction on the Norris to Mammoth section of the Grand Loop Road. This area is only 5.9 miles from the North Entrance and the town of Gardiner, Montana. It is the only thermal area in the park accessible year-round by car.
In addition to the extensive boardwalk system is the Upper Terrace Drive. This narrow, winding, one-way road is suitable for small vehicles only. It circles through the Upper Terrace area, with limited parking available near each of the features. Below we cover the boardwalk area first, followed by the drive.
There are three main parking areas for the boardwalk area. The boardwalk is all interconnected, so any of these parking areas are good. We will start at the northern end, closest to the facilities, and work south. The first feature likely to be noticed is the Liberty Cap. This unusual formation is 37 feet tall, and was created by a hot spring that was active in this location for a long time, estimated at 2,500 years. This area is now dormant, and Liberty Cap is no longer being added to.
Near Liberty Cap at the beginning of the boardwalks is Palette Spring. Here hot spring water flows down a ridge. Thermophiles, hot water loving bacteria, color the area mostly in oranges and browns.
The boardwalk leads down to the middle parking area, and then climbs, steeply at times, up the Main Terrace. Several individual sections of terrace in this area have names of their own. These include Mound, Jupiter, Cleopatra, and Minerva. The last of these is shown to the left.
Two more notable features can be accessed from the boardwalks, but the closer access is from the Upper Terrace Drive, so they will be described from there. Enter the Upper Terrace Drive 2.2 miles south of Mammoth Junction and immediately head to the right on the one-way drive. A small parking area shortly appears. This is the closest access to the Canary Spring area, pictured to the left. It is also connected to the boardwalk that starts further down by a larger parking area.
New Blue Spring
The larger parking area mentioned above provides an overlook of the entire Main Terrace Area. It also has close access to New Blue Spring, at left. This spring changes constantly, frequently going from active to inactive several times per year.
New Highland Terrace
Further around the drive are Prospect Spring and New Highland Terrace, shown to the left. The skeletons of dead trees still stand in the wake of this terrace that was created in the 1950s. It became inactive in the 1980s.
Orange Spring Mound
The road bends back to the left around Orange Spring Mound. This massive mound’s orange color is caused by the thermophiles living in the hot water emitted from vents in its top and sides.
White Elephant Back Terrace
Two more bends in the road take you to White Elephant Back Terrace. Calcium carbonate in the water escaping from a fissure builds this ridge.
Just before the loop ends and the drive rejoins the Grand Loop Road is a small parking area for Angel Terrace. This area is a good example of how dynamic the Mammoth Hot Springs area is. Angel Terrace was dry for decades, but abruptly became active again in 1985. Stranded trees, some not quite dead yet, attest to the recent change.