Semi Centennial Geyser

Gallatin County, Wyoming · Near West Yellowstone
44.7860°N, 110.7400°W · 7,540 ft
198°F 38°F air · Good soaking weather 7,540 ft Open Roadside National Park Service Camping nearby (7.0 mi)
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.

Semi Centennial Geyser is a roadside geyser in Yellowstone, about a hundred feet off the Grand Loop Road. Near-boiling water on record, with a USGS site number and a chemistry sample from 2007. Gallatin County, Park Service land, open. West Yellowstone is the town on file as nearest. A geyser, so it is there to be watched.

Location

Pull off the Grand Loop Road and it is right there, a hundred-odd feet away. Elevation around 7,500 feet. Cold climate on record, an annual average of 35, and snow running close to eleven and a half feet. Precipitation moderate. Protected national park land. Nothing is on file about the geyser's eruption pattern.

Near-boiling. Keep back from the vent and any runoff. The best months listed are the dead of winter, so confirm the Grand Loop Road is open before driving to it. Indian Creek Campground, seven miles off, is the closest camp on record. No fee listed.

History of Semi Centennial Geyser

A USGS site record exists for this geyser, with water chemistry sampled in September 2007.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around Semi Centennial Geyser.

Aerial view of the ground around Semi Centennial Geyser LiDAR bare-earth view of the same ground around Semi Centennial Geyser
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

Setting
Canyon floor
Steep ground climbs away on both sides of the spring.
Highest ground nearby
368 ft above the spring
Within a quarter mile, to the west
Cross-section through the spring

A slice through the ground from west to east, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
130 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 80% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
15°
Jan
17°
Feb
25°
Mar
30°
Apr
39°
May
50°
Jun
61°
Jul
59°
Aug
50°
Sep
34°
Oct
22°
Nov
14°
Dec
Annual Precip: 27.7 in Annual Snow: 138.2 in
Best Time to Visit
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
Current Conditions
38°F
S 24.9 mph 62% Good soaking weather
Today 59° Low 33° Sunny
Spring is +139° warmer
Wednesday 66° Low 39° Sunny
Spring is +132° warmer
Thursday 63° Low 38° Showers And Thunderstorms Likely 74% precip
Spring is +135° warmer
Friday 55° Low 33° Rain Showers Likely 62% precip
Spring is +143° warmer
Saturday 58° Low 33° Chance Showers And Thunderstorms 29% precip
Spring is +140° warmer
Water Chemistry Sampled 2007-09-18

The water at Semi Centennial Geyser is slightly acidic (pH 6.0).

pH 6.0 Slightly Acidic
pH influences mineral absorption through skin
Calcium 5 mg/L
May support bone density and joint health
Magnesium 1 mg/L
Known for muscle relaxation and stress relief
Sodium 5 mg/L
Supports circulation and skin hydration
Sulfate 2 mg/L
Traditionally used for skin conditions and inflammation
Chloride 1 mg/L
Natural antiseptic with skin health benefits
Where to Stay

Some links are affiliate links. We may earn a commission at no extra cost to you.

Nearby Camping
Indian Creek Campground (Wy) 7.0 mi away

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...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 7,540 ft

Semi Centennial Geyser sits at 7,540 feet above sea level, way above the mile-high mark. You may not feel the altitude strongly, but hot water still dehydrates you faster at elevation. UV is about 30% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

As an Amazon Associate, we earn from qualifying purchases.

Temperature
198°F
Warm Hot Boiling
Water Temp 198°F (92°C)
Avg Air Temp 35°F
Above Ambient +163°F
Access
Open
Road Access Roadside
Nearest Road Grand Loop Road
Distance to Road 113 ft
Land
Ownership Federal
Agency National Park Service
Designation National Park
Unit Yellowstone National Park
Manager National Park Service
Protection 1 - Permanent protection, natural state
Frequently Asked Questions
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?
No, not at the source. The water at Semi Centennial Geyser reaches 198°F, which can cause severe burns within seconds. Look for cooled side pools or downstream stretches, and test with a hand before anything else.
Sources: USGS NWIS