Cape Horn Warm Springs

Boise County, Idaho · Near Idaho City
44.3980°N, 115.1490°W · 6,555 ft
95°F 23°F air · Good soaking weather 6,555 ft Short Walk Camping nearby (2.1 mi)
Aerial view of the ground around Cape Horn Warm Springs LiDAR bare-earth view of the same ground around Cape Horn Warm Springs
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.

Cape Horn Warm Springs comes out at a temperature a person can sit in, around body heat, the kind of warm you can sit in for a while. It is a long way from anywhere. Idaho City, the nearest town in the record, is more than fifty miles off, and the spring sits up at sixty-five hundred feet in Boise County. Public access is not documented and no land owner is listed, so treat the legal side as an open question.

Location

You leave Beaver Creek Road and walk about seven tenths of a mile. This is high country, and the snow total is brutal, close to fifteen feet a winter, so count on the road being snowbound for a long stretch of the year. Thatcher Campground is close, around two miles. Precipitation is moderate. Nothing in the file says who manages the ground or what the walk is like.

The file rates winter highest. Square that with the snow before you plan anything. There is no burn risk at this temperature. The pH figure comes from an August 1980 sample. Access is unknown; ask before you go. Thatcher is the campground to use, and it is near enough to matter.

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 Cape Horn Warm Springs.

Setting
Hillside
The spring sits on a steep slope that climbs to the southeast.
Highest ground nearby
292 ft above the spring
Within a quarter mile, to the southeast
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
128 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 78% 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
22°
Feb
29°
Mar
33°
Apr
41°
May
51°
Jun
63°
Jul
63°
Aug
53°
Sep
38°
Oct
26°
Nov
18°
Dec
Annual Precip: 32.8 in Annual Snow: 178.8 in
Best Time to Visit
December Air 18°F · Water 95°F · +77° contrast
January Air 21°F · Water 95°F · +74° contrast
February Air 22°F · Water 95°F · +73° contrast
December offers 45°F more contrast than August
Current Conditions
23°F
N 0.0 mph 92% Good soaking weather
Today 63° Low 34° Sunny
Spring is +32° warmer
Wednesday 69° Low 39° Sunny 6% precip
Spring is +26° warmer
Thursday 63° Low 37° Chance Light Rain then Showers And Thunderstorms 83% precip
Spring is +32° warmer
Friday 62° Low 35° Chance Light Rain 43% precip
Spring is +33° warmer
Saturday 66° Low 36° Sunny 9% precip
Spring is +29° warmer
Water Chemistry Sampled 1980-08-04

The water at Cape Horn Warm Springs is alkaline (pH 9.6).

pH 9.6 Alkaline
pH influences mineral absorption through skin
Calcium 1 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 82 mg/L
Supports circulation and skin hydration
Sulfate 39 mg/L
Traditionally used for skin conditions and inflammation
Chloride 9 mg/L
Natural antiseptic with skin health benefits
Where to Stay

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Nearby Camping
Thatcher Campground 2.1 mi away

This campground is just off Highway 21, and tucked back into the trees, overlooking beautiful Capehorn meadows. Walk across the street to overlook a marshy wetland, a hangout for breakfasting moose, elk, and a variety of birds. Each of the 5 sites is equipped with picnic tables and fire rings with cooking grills. The campground accommodates trailers and motorhomes up to 32 feet and has vault toilets and hand pumps for drinking water. Although there are no full hookups, the campground will fit...

Reserve on Recreation.gov →
Mile-High Advisory 6,555 ft

Cape Horn Warm Springs sits at 6,555 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 26% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
95°F
Warm Hot Boiling
Water Temp 95°F (35°C)
Avg Air Temp 38°F
Above Ambient +57°F
Good soaking conditions September
Access
Road Access Short Walk
Nearest Road Beaver Creek Road
Distance to Road 0.7 mi
Frequently Asked Questions
What is the water temperature at Cape Horn Warm Springs?
Cape Horn Warm Springs has a water temperature of 95°F (35°C). This is a warm thermal spring.
Where is Cape Horn Warm Springs located?
Cape Horn Warm Springs is located in Boise County, Idaho at 6,555 feet elevation, near Idaho City. Coordinates: 44.3980°N, 115.1490°W.
How do I get to Cape Horn Warm Springs?
Cape Horn Warm Springs has Short Walk road access, with the nearest road being Beaver Creek Road (0.7 mi from the road).
Can I camp near Cape Horn Warm Springs?
Yes, Thatcher Campground is located nearby (2.1 miles away).
What minerals are in the water at Cape Horn Warm Springs?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 9.6 (alkaline).
Sources: USGS NWIS