At 153°F, the source water at Sacajawea 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.
Sacajawea Hot Springs blasts out at 153 degrees Fahrenheit at 5,000 feet elevation in the Boise National Forest, making it dangerously hot at the source. The spring sits just 135 feet from Grandjean Road, where its steam is impossible to miss even from a moving vehicle.
The setting is classic central Idaho mountain forest near the South Fork Payette River headwaters, east of Idaho City. Annual snowfall averages over 15 feet, and the air temperature averages 43 degrees, creating a 110-degree gap between the water and the surrounding environment. The canyon holds the smell of sulfur and wet granite. Downstream from the source, the scalding water mixes with cold creek flow, and it is in these mixing zones that temperatures become tolerable for soaking.
History of Sacajawea Hot Springs
The 153-degree source temperature and the enormous thermal differential indicate deep fault-guided circulation, likely to depths exceeding a mile beneath the surface. The Grandjean area sits at the edge of the Idaho Batholith where granitic rocks have stored residual heat for millions of years. Bonneville Campground, 11 miles west, offers access to similar geology and its own hot springs along Warm Springs Creek.
Do not touch the source water. At 153 degrees, contact causes immediate burns. Soaking is only possible downstream where cold water mixes in, and temperatures vary unpredictably. The spring is roadside on Grandjean Road, east of Lowman. Bonneville Campground, about 11 miles away, is reservable and has its own nearby hot springs. Roads close with snow, typically November through June.
Is Sacajawea Hot Springs worth visiting?
Best for
Observing powerful hot springs
Easy day trips
Overnight camping trips
Not ideal for
Casual soaking
Sacajawea Hot Springs is well suited for observing powerful hot springs and easy day trips.
Monthly Climate
26°Jan
27°Feb
33°Mar
38°Apr
45°May
56°Jun
68°Jul
67°Aug
57°Sep
43°Oct
31°Nov
23°Dec
Annual Precip: 34.1 inAnnual Snow: 184.6 in
Best Time to Visit
DecemberAir 23°F · Water 153°F · +130° contrast
JanuaryAir 26°F · Water 153°F · +127° contrast
FebruaryAir 27°F · Water 153°F · +126° contrast
December offers 45°F more contrast than July
Nearby Camping
Bonneville6.7 mi away
Overview
Bonneville Campground is 19 miles east of Lowman, Idaho just off Highway 21 at an elevation of 4,700 feet. Warm Springs Creek runs alongside the campground and the South Fork Payette River lies across the highway. Visitors enjoy soaking at Bonneville Hot Springs a short distance above the campground, and fishing in the creek and river.Recreation
A 1/4-mile hiking trail leads from the campground to Bonneville Hot Springs, where a soaking pool awaits. Warm Springs Creek offers good tro...
What is the water temperature at Sacajawea Hot Springs?
Sacajawea Hot Springs has a water temperature of 153°F (67°C). This is considered a hot spring, well above body temperature.
Where is Sacajawea Hot Springs located?
Sacajawea Hot Springs is located in Boise County, Idaho at 5,000 feet elevation, near Idaho City. Coordinates: 44.1600°N, 115.1770°W.
How do I get to Sacajawea Hot Springs?
Sacajawea Hot Springs has Roadside road access, with the nearest road being Grandjean Road (135 ft from the road).
Is Sacajawea Hot Springs free to visit?
Sacajawea Hot Springs has Open access. It is managed by US Forest Service.
Can I camp near Sacajawea Hot Springs?
Yes, Bonneville is located nearby (6.7 miles away).
Is it safe to soak at Sacajawea Hot Springs?
The water at Sacajawea Hot Springs reaches 153°F, which can cause severe burns. Do not enter the source pool directly — look for cooled side pools or downstream areas where the water has cooled to a safe temperature. Always tell someone your plans before visiting remote hot springs.
Is Sacajawea Hot Springs crowded?
Sacajawea Hot Springs 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 Sacajawea Hot Springs?
Essentials for Sacajawea Hot Springs: swimsuit, towel, water bottle, warm layers for before and after soaking, camping gear, a trash bag to pack out what you pack in. The water is over 110°F — test the temperature before entering and watch for scalding near the source.
Temperature
153°F
WarmHotBoiling
Water Temp153°F (67°C)
Avg Air Temp43°F
Above Ambient+110°F
Perfect soaking weatherMarch
Access
Open
Road AccessRoadside
Nearest RoadGrandjean Road
Distance to Road135 ft
Land
OwnershipFederal
AgencyUS Forest Service
DesignationNational Forest
UnitBoise National Forest
ManagerUS Forest Service
Protection3 - Protected, subject to extractive use