Geyser — Not a Soaking Spring
Semi Centennial Geyser is a geyser, not a traditional hot spring. These geothermal features can be extremely dangerous — boiling water, toxic gases, and unstable ground are common hazards. Do not attempt to soak.
File:Roaring Mountain (3678663181).jpg — cc by-sa 2.0
Semi-Centennial Geyser erupts at 198 degrees Fahrenheit alongside the Grand Loop Road in Yellowstone National Park, just 34 meters from pavement at 7,540 feet elevation with dilute chemistry showing minimal dissolved solids.
The geyser occupies thermal ground in Yellowstone's Roaring Mountain area where fumaroles and acidic springs alter volcanic bedrock to white and yellow clay. At 7,540 feet on the park's northern plateau, the site receives 28 inches of precipitation and 138 inches of snowfall annually. Lodgepole pine forest surrounds the thermal features, with dead standing timber marking areas of increased thermal activity. The Gallatin Range extends westward from this roadside location on the main park circuit.
History of Semi Centennial Geyser
The name commemorates the park's 50th anniversary in 1922, when thermal activity intensified at this previously quiet location. The feature demonstrates Yellowstone's dynamic hydrothermal system, with documented chemistry showing pH 6.0 and low mineral content. The geyser continues as a roadside thermal feature under National Park Service monitoring.
Visit May through October when the Grand Loop Road operates fully. Winter access requires snowcoach or ski touring. The roadside location permits viewing without hiking, though boardwalks and established paths protect thermal ground. Average annual temperature of 35 degrees means cold weather soaking is impractical; this functions as a viewing feature. Indian Creek Campground lies 11 kilometers north.
Is Semi Centennial Geyser worth visiting?
Best for
- Observing powerful hot springs
- Easy day trips
- Overnight camping trips
- Winter soaking with dramatic temperature contrast
Semi Centennial Geyser is well suited for observing powerful hot springs and easy day trips.
Annual Precip: 27.7 in
Annual Snow: 138.2 in
December
Air 14°F · Water 198°F · +184° contrast
January
Air 15°F · Water 198°F · +183° contrast
February
Air 17°F · Water 198°F · +181° contrast
December offers 47°F more contrast than July
Recent Temperature
70.0°F
(21.1°C)
Measured Sep 18, 2007
The water at Semi Centennial Geyser is slightly acidic (pH 6.0).
pH influences mineral absorption through skin
May support bone density and joint health
Known for muscle relaxation and stress relief
Supports circulation and skin hydration
Traditionally used for skin conditions and inflammation
Natural antiseptic with skin health benefits
Overview
Located about eight miles (13 km) south of Mammoth Hot Springs on the road to Norris, Indian Creek Campground—elevation 7,300 feet (2225 m)—sits near the base of the Gallatin Mountains and offers breathtaking views of Electric Peak. The area offers easy access to fishing and hiking. The campground is away from the main road and provides a quieter, more primitive, experience than many other locations.
For reservations at the campgrounds managed by Yellowstone National Park Lodges (Fi...
Reserve on Recreation.gov →
Swimsuit & towel
Water bottle
Stay hydrated, especially in hot water
Warm layers
Cold air before and after soaking
Camping gear
Nearby camping at Indian Creek Campground (Wy)
Trash bag
Pack out what you pack in
Water shoes
Hot ground near source
1 miles from West Yellowstone, WY
USGS Quad: MAMMOTH 15 · PP 492: 7.0 · Circ 790: 215.0 · NOAA: 8.0 · AMS Map: ASHTON
What is the water temperature at Semi Centennial Geyser?
Semi Centennial Geyser has a water temperature of 198°F (92°C). This is considered a hot spring, well above body temperature.
Where is Semi Centennial Geyser located?
Semi Centennial Geyser is located in Gallatin County, Wyoming at 7,540 feet elevation, near West Yellowstone. Coordinates: 44.7860°N, 110.7400°W.
How do I get to Semi Centennial Geyser?
Semi Centennial Geyser has Roadside road access, with the nearest road being Grand Loop Road (113 ft from the road).
Is Semi Centennial Geyser free to visit?
Semi Centennial Geyser has Open access. It is managed by National Park Service.
Can I camp near Semi Centennial Geyser?
Yes, Indian Creek Campground (Wy) is located nearby (7.0 miles away).
What minerals are in the water at Semi Centennial Geyser?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 6.0 (slightly acidic).
Is it safe to soak at Semi Centennial Geyser?
The water at Semi Centennial Geyser reaches 198°F, which can cause severe burns. Do not enter the source pool directly — look for cooled side pools or downstream areas where the water has cooled to a safe temperature. Always tell someone your plans before visiting remote hot springs.
Is Semi Centennial Geyser crowded?
Semi Centennial Geyser is accessible from a paved road, making it easy to reach. Weekends and holidays may be busier — consider visiting on a weekday for a quieter experience.
What should I bring to Semi Centennial Geyser?
Essentials for Semi Centennial Geyser: swimsuit, towel, water bottle, warm layers for before and after soaking, camping gear, a trash bag to pack out what you pack in. The water is over 110°F — test the temperature before entering and watch for scalding near the source.