Straight Creek Hot Spring

Boise County, Idaho · Near Idaho City
43.7880°N, 115.4440°W · 4,100 ft
144°F 33°F air · Good soaking weather 4,100 ft Open Roadside US Forest Service Camping nearby (5.2 mi)
Very Hot Source, Use Extreme Caution

At 144°F, the source water at Straight Creek Hot Spring 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 Straight Creek Hot Spring

The orange dot marks the spring, in a frame about three quarters of a mile wide.

Straight Creek Hot Spring is scalding. The recorded temperature is 144 degrees, hotter than you can hold a hand in, and it surfaces a few dozen feet from Middle Fork Road inside the Boise National Forest, Boise County, about twenty miles from Idaho City. Access is open. This is a spring to look at and, if a cooled pool exists, to test with great care.

Location

National forest at around 4,100 feet beside Middle Fork Road, sixty-odd feet from the road surface. Winters drop about ten feet of snow on average and the annual mean temperature is in the mid forties. Precipitation comes to around thirty inches a year. The land carries a National Forest designation and nothing more specific.

December through February are the recorded best months. Barber Flat Cabin is the nearest listed overnight spot, about five miles away. The water is very alkaline according to a 1981 USGS sample. Above 140 degrees the source water can burn on contact; do not step into anything you have not checked with a hand first. No fee is recorded.

Terrain

USGS hasn't flown a detailed laser scan here yet, so this view comes from aerial photos and older elevation data.

Setting
Canyon floor
Steep ground climbs away on both sides of the spring.
Highest ground nearby
672 ft above the spring
Within a quarter mile, to the south
Cross-section through the spring

A slice through the ground from south to north, about 0.6 miles end to end.

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

Heat Below
135 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 85% 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
27°
Jan
29°
Feb
36°
Mar
41°
Apr
50°
May
61°
Jun
72°
Jul
71°
Aug
61°
Sep
47°
Oct
34°
Nov
25°
Dec
Annual Precip: 29.9 in Annual Snow: 121.1 in
Best Time to Visit
December Air 25°F · Water 144°F · +119° contrast
January Air 27°F · Water 144°F · +117° contrast
February Air 29°F · Water 144°F · +115° contrast
December offers 47°F more contrast than July
Current Conditions
33°F
NW 0.0 mph 98% Good soaking weather
Tuesday 72° Low 42° Sunny
Spring is +72° warmer
Wednesday 79° Low 48° Sunny
Spring is +65° warmer
Thursday 70° Low 53° Showers And Thunderstorms 76% precip
Spring is +74° warmer
Friday 70° Low 48° Mostly Sunny then Slight Chance Rain Showers 23% precip
Spring is +74° warmer
Saturday 73° Low 47° Sunny 5% precip
Spring is +71° warmer
Water Chemistry Sampled 1981-05-28

The water at Straight Creek Hot Spring is alkaline (pH 9.6).

pH 9.6 Alkaline
pH influences mineral absorption through skin
Calcium 2 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 57 mg/L
Supports circulation and skin hydration
Sulfate 27 mg/L
Traditionally used for skin conditions and inflammation
Chloride 2 mg/L
Natural antiseptic with skin health benefits
Nearby Camping
Nearby Camping
Barber Flat Cabin (Boise National Forest, Id) 5.2 mi away

Overview The Barber Flat Cabin site was established for administrative use by the Forest Service in 1923, and was used prior to that by the Barber Lumber Company. At the time, the Forest Service used a cabin already on-site as a guard station and then built a new one in 1927. The current cabin and outbuildings were built by the Civilian Conservation Corps in 1935, and the cabin today looks much as it did back then. Guests can drive to Barber Flat Cabin in two-wheel drive passenger cars or tr...

Reservable Yes
Reserve on Recreation.gov →
Temperature
144°F
Warm Hot Boiling
Water Temp 144°F (62°C)
Avg Air Temp 46°F
Above Ambient +98°F
Great soaking conditions September
Access
Open
Road Access Roadside
Nearest Road Middle Fork Road
Distance to Road 68 ft
Land
Ownership Federal
Agency US Forest Service
Designation National Forest
Unit Boise National Forest
Manager US Forest Service
Protection 3 - Protected, subject to extractive use
Frequently Asked Questions
What is the water temperature at Straight Creek Hot Spring?
Straight Creek Hot Spring has a water temperature of 144°F (62°C). This is considered a hot spring, well above body temperature.
Where is Straight Creek Hot Spring located?
Straight Creek Hot Spring is located in Boise County, Idaho at 4,100 feet elevation, near Idaho City. Coordinates: 43.7880°N, 115.4440°W.
How do I get to Straight Creek Hot Spring?
Straight Creek Hot Spring has Roadside road access, with the nearest road being Middle Fork Road (68 ft from the road).
Is Straight Creek Hot Spring free to visit?
Straight Creek Hot Spring has Open access. It is managed by US Forest Service.
Can I camp near Straight Creek Hot Spring?
Yes, Barber Flat Cabin (Boise National Forest, Id) is located nearby (5.2 miles away).
What minerals are in the water at Straight Creek Hot Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 9.6 (alkaline).
Is it safe to soak at Straight Creek Hot Spring?
No, not at the source. The water at Straight Creek Hot Spring reaches 144°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