Mammoth Hot Springs

Gallatin County, Wyoming · Near West Yellowstone
44.9670°N, 110.7080°W · 6,589 ft
163°F 38°F air · Good soaking weather 6,589 ft Open Roadside National Park Service Camping nearby (0.9 mi)
Very Hot Source, Use Extreme Caution

At 163°F, the source water at Mammoth Hot Springs is hot enough to cause burns. Some hot springs this hot have cooler side pools or downstream areas suitable for soaking. Always test the water temperature before entering.

Mammoth Hot Springs is the big complex of hot springs on a travertine hill in Yellowstone National Park, Gallatin County, with a measured temperature hot enough to scald. It sits right beside Upper Terrace Drive. People come to look at the travertine, and there is a campground under a mile away. Park Service land, public access open.

Location

Upper Terrace Drive runs within twenty feet of the springs, so this is a roadside stop. The springs rise on a hill of travertine. The elevation is around sixty-six hundred feet. Snowfall runs a bit over nine feet a year; the mean for the year is in the upper thirties. Precipitation is about two feet a year.

Best months on record are December through February. Mammoth Campground, less than a mile off, is the camping on record. The water is scalding; keep to established ground. Access is open and roadside, no fee recorded. With the road that near, winter access comes down to plowing, and the park sets that.

History of Mammoth Hot Springs

The travertine hill built up over thousands of years as hot water cooled at the surface and dropped calcium carbonate, the mineral that builds travertine. By one estimate more than two tons of it come up in solution every day, and the sheer number of vents keeps the travertine growing. The complex sits next to Fort Yellowstone and the Mammoth Hot Springs Historic District.

Then & Now

Liberty Cap, the 37-foot cone of a spring that went dormant long ago, has hardly changed since William Henry Jackson photographed it in 1871. The bare hillside behind it has filled in with trees.

Mammoth Hot Springs in 1871 Mammoth Hot Springs in 2021
1871 2021

Drag to compare.

1871: William Henry Jackson, Yellowstone National Park archive, public domain. 2021: Steven Pavlov, CC BY-SA 4.0.

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 Mammoth Hot Springs.

Aerial view of the ground around Mammoth Hot Springs LiDAR bare-earth view of the same ground around Mammoth Hot Springs
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
Hillside
The spring sits on a steep slope that climbs to the southwest.
Highest ground nearby
190 ft above the spring
Within a quarter mile, to the southwest
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.

Seen From Space

Landsat's thermal camera passed over on a clear winter day, December 3, 2022. This spring's heat shows up from about 440 miles up. The brightest yellow marks the warmest ground, roughly 9°F warmer than the land around it.

Aerial view of the ground around Mammoth Hot Springs Landsat thermal view of the same ground around Mammoth Hot Springs
Aerial Thermal

Drag to compare. The view is about 2½ miles across, and each thermal pixel covers roughly 300 feet of ground, so individual pools blur into one warm patch.

Thermal: Landsat 8/9 surface temperature, USGS (public domain), via Microsoft Planetary Computer. Aerial: USGS The National Map. More springs seen from space.

Heat Below
110 milliwatts per square meter of heat flow

That's about 1½ times the US average of 65. It's higher than at 61% 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
16°
Jan
19°
Feb
27°
Mar
33°
Apr
41°
May
53°
Jun
63°
Jul
61°
Aug
52°
Sep
36°
Oct
23°
Nov
14°
Dec
Annual Precip: 24.1 in Annual Snow: 110.2 in
Best Time to Visit
December Air 14°F · Water 163°F · +149° contrast
January Air 16°F · Water 163°F · +147° contrast
February Air 19°F · Water 163°F · +144° contrast
December offers 49°F more contrast than July
Current Conditions
38°F
S 24.9 mph 62% Good soaking weather
Today 62° Low 37° Sunny
Spring is +101° warmer
Wednesday 68° Low 43° Sunny
Spring is +95° warmer
Thursday 65° Low 44° Showers And Thunderstorms Likely 66% precip
Spring is +98° warmer
Friday 59° Low 39° Showers And Thunderstorms Likely 63% precip
Spring is +104° warmer
Saturday 62° Low 38° Chance Showers And Thunderstorms 34% precip
Spring is +101° warmer
Where to Stay

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Nearby Camping
Mammoth Campground (Yellowstone) 0.9 mi away

Overview Starting Tuesday April 15th, the Mammoth Campground is open and reservations are required. For reservations at the campgrounds managed by Yellowstone National Park Lodges (Fishing Bridge RV Park, Bridge Bay, Canyon, Madison, and Grant Village campgrounds), please visit the Yellowstone National Park Lodges Camping website. Recreation There are many recreational opportunities in the Mammoth Hot Springs and the North area. Visit these pages to learn more:Boating   Fishing   Hiking Phot...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 6,589 ft

Mammoth Hot Springs sits at 6,589 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 26% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
163°F
Warm Hot Boiling
Water Temp 163°F (73°C)
Avg Air Temp 37°F
Above Ambient +127°F
Great soaking conditions September
Access
Open
Road Access Roadside
Nearest Road Upper Terrace Drive
Distance to Road 20 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 Mammoth Hot Springs?
Mammoth Hot Springs has a water temperature of 163°F (73°C). This is considered a hot spring, well above body temperature.
Where is Mammoth Hot Springs located?
Mammoth Hot Springs is located in Gallatin County, Wyoming at 6,589 feet elevation, near West Yellowstone. Coordinates: 44.9670°N, 110.7080°W.
How do I get to Mammoth Hot Springs?
Mammoth Hot Springs has Roadside road access, with the nearest road being Upper Terrace Drive (20 ft from the road).
Is Mammoth Hot Springs free to visit?
Mammoth Hot Springs has Open access. It is managed by National Park Service.
Can I camp near Mammoth Hot Springs?
Yes, Mammoth Campground (Yellowstone) is located nearby (0.9 miles away).
Is it safe to soak at Mammoth Hot Springs?
No, not at the source. The water at Mammoth Hot Springs reaches 163°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: Wikipedia