Roystone Hot Springs
Roystone Hot Springs reaches a scalding 151 degrees Fahrenheit in Gem County, creating a 98-degree differential with the average air temperature. That extreme heat makes this one of the hottest springs in the Emmett area, visible by its steam plume rising near East Black Canyon Highway.
The spring sits at 2,530 feet elevation in the low foothills east of Emmett, where the landscape is drier and more open than Idaho's mountain interior. Annual precipitation runs about 21 inches with modest snowfall of 33 inches. The terrain is characterized by rocky slopes and sparse vegetation. A short walk of roughly 540 feet from the highway leads to the source, where the water is far too hot to touch without significant cooling.
The 151-degree temperature indicates deep fault-controlled circulation, likely along the western margin of the Idaho Batholith where it meets the older metamorphic rocks of the Black Canyon area. The extreme heat and low elevation combine to produce one of the largest thermal-to-ambient differentials in Idaho. Development of the nearby highway corridor has made the spring easily observable but has not altered the geothermal source.
Do not enter the source water. At 151 degrees, it causes severe burns on contact. Any soaking requires substantial mixing with cold creek water downstream. The spring is a short walk from East Black Canyon Highway near Emmett. The nearest reservable campground is Shafer Butte, roughly 29 miles away near Bogus Basin. This is a look-and-observe feature for most visitors.
Is Roystone Hot Springs worth visiting?
Best for
- Observing powerful hot springs
- Overnight camping trips
Not ideal for
- Casual soaking
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Overview Shafer Butte is located atop the scenic Boise Ridge Mountains, near Bogus Basin Mountain Recreation Area, at an elevation of 7,000 feet. Visitors enjoy hiking and biking on various trails in the surrounding area, and simply relaxing and taking in the area's beautiful views.Recreation Popular activities in the area include hiking and mountain biking, the Mores Mountain Trail begins in the campground. This 2-mile interpretive nature trail is family friendly. Facilities Shafer Butte con...