Smith Cabin Hot Spring

Boise County, Idaho · Near Idaho City
43.7200°N, 115.6170°W · 3,560 ft
138°F 33°F air · Good soaking weather 3,560 ft Open Roadside US Forest Service Camping nearby (3.5 mi)
Aerial view of the ground around Smith Cabin Hot Spring LiDAR bare-earth view of the same ground around Smith Cabin Hot Spring
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.

Boise National Forest holds Smith Cabin Hot Spring, a roadside spring thirteen miles from Idaho City in Boise County. It is hot, near the top of the hot range, strongly alkaline on the 1981 sample. The public can go. OpenStreetMap carries the same name as the record, Smith Cabin Hot Spring, so there is no confusion over what to call it.

Location

Middle Fork Road runs about sixty feet from the water, close enough that you could step out of a vehicle and be there in moments. Low elevation for the forest. Snow totals are heavy, a bit over nine feet, with a moderately wet year. Designation on file is national forest.

Ninemeyer Campground is three or four miles away. The record gives December through February as the best season, and whatever nine feet of snow has done to Middle Fork Road by then is worth asking about first. Straight from the ground the water will hurt; let it mix with something cooler first. Forest Service ground, no access restriction on file.

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 Smith Cabin Hot Spring.

Setting
Canyon floor
Steep ground climbs away on both sides of the spring.
Highest ground nearby
493 ft above the spring
Within a quarter mile, to the northwest
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
138 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 88% 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
32°
Feb
38°
Mar
44°
Apr
54°
May
64°
Jun
75°
Jul
75°
Aug
64°
Sep
50°
Oct
37°
Nov
28°
Dec
Annual Precip: 28.8 in Annual Snow: 110.1 in
Best Time to Visit
December Air 28°F · Water 138°F · +110° contrast
January Air 30°F · Water 138°F · +109° contrast
February Air 32°F · Water 138°F · +106° contrast
December offers 47°F more contrast than July
Current Conditions
33°F
NW 0.0 mph 98% Good soaking weather
Today 76° Low 48° Sunny
Spring is +62° warmer
Wednesday 82° Low 53° Sunny
Spring is +56° warmer
Thursday 74° Low 48° Showers And Thunderstorms Likely 73% precip
Spring is +64° warmer
Friday 74° Low 47° Mostly Sunny then Slight Chance Rain Showers 19% precip
Spring is +64° warmer
Saturday 77° Low 49° Sunny 5% precip
Spring is +61° warmer
Water Chemistry Sampled 1981-08-03

The water at Smith Cabin Hot Spring is alkaline (pH 9.5).

pH 9.5 Alkaline
pH influences mineral absorption through skin
Calcium 2 mg/L
May support bone density and joint health
Sodium 44 mg/L
Supports circulation and skin hydration
Sulfate 18 mg/L
Traditionally used for skin conditions and inflammation
Chloride 2 mg/L
Natural antiseptic with skin health benefits
Nearby Camping
Nearby Camping
Ninemeyer Campground 3.5 mi away

Overview:Due to a wildfire, there are no amenities at the campground.  Currently there are no developed campfire rings therefore when Stage 1 fire restrictions area in effect, no fires are permitted.A stay at Ninemeyer Campground enables guests to enjoy all the beauty and recreation offered along the (Middle Fork Boise River Road) Forest Service (FS) Road 268. Weather is usually good from mid-May through late September and is easily accessible by car in good weather, although the road is some...

Reserve on Recreation.gov →
Temperature
138°F
Warm Hot Boiling
Water Temp 138°F (59°C)
Avg Air Temp 49°F
Above Ambient +89°F
Great soaking conditions September
Access
Open
Road Access Roadside
Nearest Road Middle Fork Road
Distance to Road 65 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 Smith Cabin Hot Spring?
Smith Cabin Hot Spring has a water temperature of 138°F (59°C). This is considered a hot spring, well above body temperature.
Where is Smith Cabin Hot Spring located?
Smith Cabin Hot Spring is located in Boise County, Idaho at 3,560 feet elevation, near Idaho City. Coordinates: 43.7200°N, 115.6170°W.
How do I get to Smith Cabin Hot Spring?
Smith Cabin Hot Spring has Roadside road access, with the nearest road being Middle Fork Road (65 ft from the road).
Is Smith Cabin Hot Spring free to visit?
Smith Cabin Hot Spring has Open access. It is managed by US Forest Service.
Can I camp near Smith Cabin Hot Spring?
Yes, Ninemeyer Campground is located nearby (3.5 miles away).
What minerals are in the water at Smith Cabin Hot Spring?
Water chemistry analysis shows the presence of pH, Calcium, Sodium, Sulfate, Chloride. The pH is 9.5 (alkaline).
Is it safe to soak at Smith Cabin Hot Spring?
With care. At 138°F Smith Cabin Hot Spring is hot enough to need short sessions, fifteen to twenty minutes, and plenty of water. Enter slowly and get out if you feel light-headed.