West Pass Hot Spring

Blaine County, Idaho · Near Sun Valley
43.9820°N, 114.4860°W · 6,795 ft
124°F 6,795 ft Open Roadside US Forest Service Camping nearby (13.1 mi)

West Pass Hot Spring delivers 124°F water at 6,795 feet elevation in the Sawtooth National Forest, one of Idaho's higher-altitude hot springs. Roadside access places it just 18.1 meters from the road on open public land near Sun Valley. Alkaline chemistry (pH 8.5) with elevated sodium at 110 mg/L indicates deep geothermal sourcing.

Location

The spring emerges in the high mountain terrain of Blaine County, surrounded by subalpine meadows and conifer forests typical of the Sawtooth Range's eastern flanks. Annual snowfall averages over 134 inches, and the mean annual air temperature sits at 39°F, producing long winters and short growing seasons. The Big Wood River drainage stretches south toward Ketchum and Sun Valley. Peaks and ridgelines of the Boulder and Smoky Mountains frame the horizon.

The high elevation means snow blocks access from roughly November through May. Summer and early fall provide the best window, though afternoon thunderstorms are common. The roadside location makes this one of the more easily reached high-altitude hot springs. Water temperature at 124°F requires mixing with cooler water before soaking. Wood River Campground, 21 km south, is reservable and sits along the Big Wood River at 6,400 feet.

History of West Pass Hot Spring

Limited historical documentation exists for this specific spring beyond its inclusion in geothermal surveys. The Sawtooth National Forest, established in 1905, encompasses the site. The spring sits within the broader Sawtooth National Recreation Area, designated by Congress in 1972 to balance recreation and resource management. Its proximity to Sun Valley, developed as a ski resort in 1936, places it in one of Idaho's earliest recreational corridors.

Monthly Climate
22°
Jan
22°
Feb
28°
Mar
33°
Apr
42°
May
52°
Jun
64°
Jul
63°
Aug
54°
Sep
39°
Oct
28°
Nov
19°
Dec
Annual Precip: 25.4 in Annual Snow: 134.3 in
Best Time to Visit
December Air 19°F · Water 124°F · +105° contrast
January Air 22°F · Water 124°F · +102° contrast
February Air 22°F · Water 124°F · +102° contrast
December offers 45°F more contrast than July
Current Conditions
41°F
SSE 16.9 mph 70% Good soaking weather
Thursday 59° Low 39° Sunny
Spring is +65° warmer
Friday 60° Low 37° Mostly Sunny
Spring is +64° warmer
Saturday 61° Low 36° Sunny
Spring is +63° warmer
Sunday 65° Low 38° Sunny
Spring is +59° warmer
Monday 66° Low 41° Sunny
Spring is +58° warmer
Water Chemistry Sampled 1980-08-07

The water at West Pass Hot Spring is slightly alkaline (pH 8.5).

pH 8.5 Slightly Alkaline
pH influences mineral absorption through skin
Calcium 20 mg/L
May support bone density and joint health
Magnesium 5 mg/L
Known for muscle relaxation and stress relief
Sodium 110 mg/L
Supports circulation and skin hydration
Sulfate 83 mg/L
Traditionally used for skin conditions and inflammation
Chloride 39 mg/L
Natural antiseptic with skin health benefits
Where to Stay

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Nearby Camping
Wood River Group Overnight Area (Tent Only) 13.1 mi away

Overview Wood River Group Overnight Area is located inside the Wood River Campground, which has 30 single campsites for RV's and tent camping, which are available for use on a first-come first-served basis. This campground is located on the banks of the beautiful Big Wood River at an elevation of 6400 feet. Ketchum, Idaho is conveniently close, only 10 miles south. Visitors enjoy fishing, tubing and exploring local trails.Recreation This site is part of the Sawtooth National Recreation Area,...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 6,795 ft

West Pass Hot Spring sits at 6,795 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 27% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
124°F
Warm Hot Boiling
Water Temp 124°F (51°C)
Avg Air Temp 39°F
Above Ambient +85°F
Great soaking conditions May
Access
Open
Road Access Roadside
Distance to Road 59 ft
Land
Ownership Federal
Agency US Forest Service
Designation National Forest
Unit Sawtooth National Forest
Manager US Forest Service
Protection 3 - Protected, subject to extractive use
Frequently Asked Questions
What is the water temperature at West Pass Hot Spring?
West Pass Hot Spring has a water temperature of 124°F (51°C). This is considered a hot spring, well above body temperature.
Where is West Pass Hot Spring located?
West Pass Hot Spring is located in Blaine County, Idaho at 6,795 feet elevation, near Sun Valley. Coordinates: 43.9820°N, 114.4860°W.
How do I get to West Pass Hot Spring?
West Pass Hot Spring has Roadside road access (59 ft from the road).
Is West Pass Hot Spring free to visit?
West Pass Hot Spring has Open access. It is managed by US Forest Service.
Can I camp near West Pass Hot Spring?
Yes, Wood River Group Overnight Area (Tent Only) is located nearby (13.1 miles away).
What minerals are in the water at West Pass Hot Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 8.5 (slightly alkaline).
Is it safe to soak at West Pass Hot Spring?
At 124°F, West Pass Hot Spring is hot enough to require caution. Enter slowly, limit soaking sessions to 15–20 minutes, and stay hydrated. Always tell someone your plans before visiting remote hot springs.
Is West Pass Hot Spring crowded?
West Pass Hot Spring 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 West Pass Hot Spring?
Essentials for West Pass Hot Spring: 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.
Sources: USGS NWIS