Roystone Hot Springs

Gem County, Idaho · Near Emmett
43.9510°N, 116.3530°W · 2,530 ft
151°F 35°F air · Good soaking weather 2,530 ft Short Walk Camping nearby (17.7 mi)
Very Hot Source, Use Extreme Caution

At 151°F, the source water at Roystone 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.

Aerial view of the ground around Roystone Hot Springs LiDAR bare-earth view of the same ground around Roystone 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.

Roystone Hot Springs is in Gem County, about nine miles from Emmett, and the water is scalding. The USGS reading sits well above what skin can take, so this is no place to get in without knowing the flow has cooled somewhere. Nothing on file names an owner or says if you can visit. No water chemistry is recorded.

Location

East Black Canyon Highway is about a tenth of a mile off, a short walk. The spring sits low, where the yearly average is mild. Snow is light, under three feet a year, and precipitation is modest. Emmett is the closest town in the record.

Shafer Butte campground is the nearest listed, about eighteen miles away. Midwinter is the recommended time, January first. The source temperature is far above safe. Do not touch the outflow directly and keep pets and children away from it. With no owner recorded, confirm you are allowed there before visiting. No chemistry has been taken, so what the water carries is anyone's guess.

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 Roystone Hot Springs.

Setting
Gentle slope
The ground tilts gently up to the southeast.
Highest ground nearby
147 ft above the spring
Within a quarter mile, to the southeast
Cross-section through the spring

A slice through the ground from northwest to southeast, about 0.6 miles end to end.

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

Heat Below
87 milliwatts per square meter of heat flow

That's about 1½ times the US average of 65. It's higher than at 26% 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
30°
Jan
36°
Feb
44°
Mar
50°
Apr
60°
May
69°
Jun
79°
Jul
78°
Aug
68°
Sep
53°
Oct
40°
Nov
30°
Dec
Annual Precip: 20.6 in Annual Snow: 32.9 in
Best Time to Visit
January Air 30°F · Water 151°F · +121° contrast
December Air 30°F · Water 151°F · +121° contrast
February Air 36°F · Water 151°F · +116° contrast
January offers 49°F more contrast than July
Current Conditions
35°F
Good soaking weather
Today 82° Low 48° Sunny
Spring is +69° warmer
Wednesday 87° Low 52° Sunny
Spring is +64° warmer
Thursday 81° Low 50° Rain Showers Likely 56% precip
Spring is +70° warmer
Friday 82° Low 49° Sunny 12% precip
Spring is +69° warmer
Saturday 84° Low 50° Sunny 2% precip
Spring is +67° warmer
Nearby Camping
Nearby Camping
Shafer Butte 17.7 mi away

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...

Reservable Yes
Reserve on Recreation.gov →
Temperature
151°F
Warm Hot Boiling
Water Temp 151°F (66°C)
Avg Air Temp 53°F
Above Ambient +98°F
Great soaking conditions September
Access
Road Access Short Walk
Nearest Road East Black Canyon Highway
Distance to Road 0.1 mi
Frequently Asked Questions
What is the water temperature at Roystone Hot Springs?
Roystone Hot Springs has a water temperature of 151°F (66°C). This is considered a hot spring, well above body temperature.
Where is Roystone Hot Springs located?
Roystone Hot Springs is located in Gem County, Idaho at 2,530 feet elevation, near Emmett. Coordinates: 43.9510°N, 116.3530°W.
How do I get to Roystone Hot Springs?
Roystone Hot Springs has Short Walk road access, with the nearest road being East Black Canyon Highway (0.1 mi from the road).
Can I camp near Roystone Hot Springs?
Yes, Shafer Butte is located nearby (17.7 miles away).
Is it safe to soak at Roystone Hot Springs?
No, not at the source. The water at Roystone Hot Springs reaches 151°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