Portneuf River Warm Spring

Caribou County, Idaho · Near Soda Springs
42.7810°N, 111.9830°W · 5,308 ft
93°F 5,308 ft Short Walk Camping nearby (5.5 mi)
Aerial view of the ground around Portneuf River Warm Spring LiDAR bare-earth view of the same ground around Portneuf River Warm 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.

Portneuf River Warm Spring, in Caribou County, is about 22 miles from Soda Springs. Soaking warm is the category here, low nineties when measured in 1977, with a trickle of flow and slightly acidic water. Who holds the land is unknown, and so is your right to be there. OpenStreetMap has no second name for it.

Location

Kelly Toponce Road is the approach, roughly five hundred feet away, which makes for a short walk. The country is high, averaging in the mid forties across the year, with close to six feet of snow each winter and modest precipitation otherwise.

Pebble Guard Station is the nearest camp on record, five or six miles off. Winter months are the ones the record recommends. Flow was measured at a tenth of a cubic foot per second, which is very little, so the volume of water is small. Land status is unknown; find out before you go. The reading is from 1977.

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 Portneuf River Warm Spring.

Setting
Gentle slope
The ground tilts gently up to the north.
Highest ground nearby
116 ft above the spring
Within a quarter mile, to the north
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
96 milliwatts per square meter of heat flow

That's about 1½ times the US average of 65. It's higher than at 42% 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
21°
Jan
25°
Feb
33°
Mar
40°
Apr
51°
May
62°
Jun
72°
Jul
70°
Aug
60°
Sep
45°
Oct
32°
Nov
20°
Dec
Annual Precip: 20.4 in Annual Snow: 70.5 in
Best Time to Visit
December Air 20°F · Water 93°F · +73° contrast
January Air 21°F · Water 93°F · +72° contrast
February Air 25°F · Water 93°F · +69° contrast
December offers 52°F more contrast than July
Current Conditions
Today 74° Low 39° Mostly Sunny
Spring is +19° warmer
Wednesday 77° Low 47° Sunny 14% precip
Spring is +16° warmer
Thursday 73° Low 41° Light Rain Likely then Chance Showers And Thunderstorms 74% precip
Spring is +20° warmer
Friday 71° Low 36° Mostly Sunny then Slight Chance Light Rain 19% precip
Spring is +22° warmer
Saturday 72° Low 36° Sunny 6% precip
Spring is +21° warmer
Water Chemistry Sampled 1977-08-23

The water at Portneuf River Warm Spring is slightly acidic (pH 6.2). It is notably rich in calcium (may support bone density and joint health), magnesium (known for muscle relaxation and stress relief), and sulfate (traditionally used for skin conditions and inflammation).

pH 6.2 Slightly Acidic
pH influences mineral absorption through skin
Calcium 280 mg/L
May support bone density and joint health
Magnesium 64 mg/L
Known for muscle relaxation and stress relief
Sodium 81 mg/L
Supports circulation and skin hydration
Sulfate 270 mg/L
Traditionally used for skin conditions and inflammation
Chloride 62 mg/L
Natural antiseptic with skin health benefits
Nearby Camping
Nearby Camping
Pebble Guard Station 5.5 mi away

Overview Pebble Guard Station is located at the base of Bonneville Peak along beautiful Pebble Creek, a tributary of the Portneuf River. The rustic one-room cabin offers a secluded retreat on four fenced acres, surrounded by high mountain vistas. The original Pebble Guard Station was built in 1908. The current structure stands at a higher altitude and was built in 1933.Guests can drive to Pebble Guard Station during warmer months, but it can only be accessed by snowmobile or other snow means...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 5,308 ft

Portneuf River Warm Spring sits at 5,308 feet above sea level, way above the mile-high mark. You may not feel the altitude strongly, but hot water still dehydrates you faster at elevation. UV is about 21% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
93°F
Warm Hot Boiling
Water Temp 93°F (34°C)
Avg Air Temp 44°F
Above Ambient +49°F
Good soaking conditions September
Access
Road Access Short Walk
Nearest Road Kelly Toponce Road
Distance to Road 0.1 mi

Hike 1 waterfall near Portneuf River Warm Spring

Looking for more outdoor adventures? Explore waterfall hikes near Portneuf River Warm Spring, Idaho.

Frequently Asked Questions
What is the water temperature at Portneuf River Warm Spring?
Portneuf River Warm Spring has a water temperature of 93°F (34°C). This is a warm thermal spring.
Where is Portneuf River Warm Spring located?
Portneuf River Warm Spring is located in Caribou County, Idaho at 5,308 feet elevation, near Soda Springs. Coordinates: 42.7810°N, 111.9830°W.
How do I get to Portneuf River Warm Spring?
Portneuf River Warm Spring has Short Walk road access, with the nearest road being Kelly Toponce Road (0.1 mi from the road).
Can I camp near Portneuf River Warm Spring?
Yes, Pebble Guard Station is located nearby (5.5 miles away).
What minerals are in the water at Portneuf River Warm Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 6.2 (slightly acidic).
Sources: USGS NWIS