File:M 4411161 nw 12 060 20210614.tif — public domain
Ashton Warm Spring emerges at 79 degrees Fahrenheit in Fremont County, placing it below typical soaking temperature but above the surrounding creeks fed by snowmelt. With a near-neutral pH of 7.9 and trace iron content, the water carries a faintly mineral character. A short walk of about 160 meters from Idaho Medal of Honor Highway reaches the source.
The spring sits at 5,200 feet where the upper Snake River Plain transitions into the forested foothills approaching Yellowstone country. Lodgepole pine and mixed conifers frame the approach. Annual snowfall averages over five feet, and the ground stays white well into spring. Summer days are mild, rarely exceeding the mid-80s. The warm water contrasts sharply with the cold streams draining the nearby Caribou-Targhee National Forest.
History of Ashton Warm Spring
This stretch of eastern Idaho lies along the western margin of the Yellowstone volcanic system, where deep heat gradually diminishes with distance from the caldera. Ashton itself was established as a railroad town in 1906 and became a gateway to Yellowstone's western entrances. The spring's moderate temperature reflects shallower circulation through fractured volcanic rock rather than contact with deep magmatic heat sources.
A short walk from Idaho Medal of Honor Highway leads to the spring, though the path may be uneven. Warm River Campground, 12 miles away in the Caribou-Targhee National Forest, offers reservable sites and river tubing. Water temperature sits below comfortable soaking range for most visitors, functioning better as a foot soak or curiosity. Best visited June through September when roads and trails are clear.
Is Ashton Warm Spring worth visiting?
Ashton Warm Spring is well suited for overnight camping trips.
Annual Precip: 20.5 in
Annual Snow: 63.5 in
December
Air 18°F · Water 79°F · +61° contrast
January
Air 19°F · Water 79°F · +60° contrast
February
Air 23°F · Water 79°F · +56° contrast
December offers 51°F more contrast than July
Recent Temperature
103.1°F
(39.5°C)
Measured Sep 06, 1977
The water at Ashton Warm Spring is slightly alkaline (pH 7.9).
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
Iron-rich springs may support circulation
Overview
Warm River Campground is located on its namesake in the Caribou-Targhee National Forest of southwestern Idaho. Visitors love the campground for its river tubing opportunities. Fishing and hiking are popular as well. Recreation
Warm River is a popular location for tubing and fishing. Anglers cast for whitefish, brook, rainbow and cutthroat trout.
Numerous hiking, mountain biking and horseback riding trails are in the immediate area, leading to natural springs, waterfalls and old rai...
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 Warm River
Trash bag
Pack out what you pack in
USGS Quad: (ASHTON 7.5) · Circ 790: 116.0 · NOAA: 1.0 · AMS Map: ASHTON
What is the water temperature at Ashton Warm Spring?
Ashton Warm Spring has a water temperature of 79°F (26°C). This is a warm thermal spring.
Where is Ashton Warm Spring located?
Ashton Warm Spring is located in Fremont County, Idaho at 5,201 feet elevation, near Ashton. Coordinates: 44.0910°N, 111.4580°W.
How do I get to Ashton Warm Spring?
Ashton Warm Spring has Short Walk road access, with the nearest road being Idaho Medal of Honor Highway (0.1 mi from the road).
Can I camp near Ashton Warm Spring?
Yes, Warm River is located nearby (7.5 miles away).
What minerals are in the water at Ashton Warm Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride, Iron. The pH is 7.9 (slightly alkaline).
Is it safe to soak at Ashton Warm Spring?
Ashton Warm Spring is generally safe for soaking at its recorded temperature. Access may be on private land or unconfirmed — verify current conditions before visiting. Always tell someone your plans before visiting remote hot springs.
Is Ashton Warm Spring crowded?
Ashton Warm Spring sees varying levels of visitors depending on the season and day of the week.
What should I bring to Ashton Warm Spring?
Essentials for Ashton Warm Spring: swimsuit, towel, water bottle, warm layers for before and after soaking, camping gear, a trash bag to pack out what you pack in.