File:IDAHO-B-0007 Salmon River - Stanley.jpg — cc by-sa 2.0
Stanley Hot Spring sits just 66 feet from the Salmon River Scenic Byway at 6,220 feet elevation, making it one of the easiest thermal features to reach in Idaho's Challis National Forest. The 106-degree water provides a comfortable soaking temperature without needing to mix in cold water.
Pulling off the scenic byway, the spring is essentially at the roadside in the heart of Custer County. The Salmon River runs nearby through a forested valley that collects over 12 feet of snow each winter. At 39.6 degrees average annual air temperature, this is cold country, and the spring's 66.4-degree thermal surplus above ambient makes the warm water feel especially inviting. Alkaline water with a pH of 8.8 has a slippery, soft quality that distinguishes it from the river water just steps away.
History of Stanley Hot Spring
The spring draws from the same deep geothermal system that heats dozens of features across the Sawtooth and Salmon River region. Water chemistry shows low mineralization with just 60 mg/L sodium and 31 mg/L sulfate, indicating rapid circulation through clean granite rather than prolonged contact with sedimentary rock. The Challis National Forest encompasses some of Idaho's most thermally active terrain, a consequence of the shallow magmatic intrusions beneath the region.
Park along the Salmon River Scenic Byway and walk less than a minute to the spring. The 106-degree temperature is comfortable for direct soaking. Sunny Gulch Campground, about 3.5 miles away along the Salmon River, accepts reservations and provides a convenient base. The scenic byway itself offers outstanding driving between Stanley and Challis. The spring is accessible whenever the highway is clear, typically May through November.
Is Stanley Hot Spring worth visiting?
Best for
- Hot spring soaking
- Easy day trips
- Overnight camping trips
- Winter soaking with dramatic temperature contrast
Stanley Hot Spring offers an accessible hot spring experience — great for a day trip.
Annual Precip: 27.3 in
Annual Snow: 146.4 in
December
Air 19°F · Water 106°F · +87° contrast
January
Air 22°F · Water 106°F · +84° contrast
February
Air 24°F · Water 106°F · +83° contrast
December offers 46°F more contrast than July
Recent Temperature
105.8°F
(41.0°C)
Measured Jul 12, 1972
The water at Stanley Hot Spring is alkaline (pH 8.8).
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
Sunny Gulch Campground sits along the shores of Salmon River in the forests of central Idaho. Recreation
Excellent fishing is right out your back door on the Salmon River, with rainbow trout, Westslope cutthroat trout and occasional hybrid cutbows and bull trout available.
Sunny Gulch lies in the heart of the Sawtooth National Recreation Area. A myriad of excellent hiking and biking opportunities are available, and an estimated 750 miles of trails crisscross the valley and surround...
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 Sunny Gulch Campground
Trash bag
Pack out what you pack in
USGS Quad: STANLEY 7.5 · PP 492: 94.0 · NOAA: 20.0 · AMS Map: CHALLIS
What is the water temperature at Stanley Hot Spring?
Stanley Hot Spring has a water temperature of 106°F (41°C). This is considered a hot spring, well above body temperature.
Where is Stanley Hot Spring located?
Stanley Hot Spring is located in Custer County, Idaho at 6,220 feet elevation, near Challis. Coordinates: 44.2240°N, 114.9290°W.
How do I get to Stanley Hot Spring?
Stanley Hot Spring has Roadside road access, with the nearest road being Salmon River Scenic Byway (66 ft from the road).
Is Stanley Hot Spring free to visit?
Stanley Hot Spring has Open access. It is managed by US Forest Service.
Can I camp near Stanley Hot Spring?
Yes, Sunny Gulch Campground is located nearby (3.5 miles away).
What minerals are in the water at Stanley Hot Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 8.8 (alkaline).
Is it safe to soak at Stanley Hot Spring?
Stanley Hot Spring is generally safe for soaking at its recorded temperature. Always tell someone your plans before visiting remote hot springs.
Is Stanley Hot Spring crowded?
Stanley Hot Spring 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 Stanley Hot Spring?
Essentials for Stanley Hot Spring: swimsuit, towel, water bottle, warm layers for before and after soaking, camping gear, a trash bag to pack out what you pack in.