Blackfoot Reservoir Warm Spring
Blackfoot Reservoir Warm Spring sits at 72 degrees Fahrenheit near the shores of southeastern Idaho's second-largest reservoir. At 6,162 feet elevation in Caribou County, the spring runs 30 degrees above the local average air temperature, a modest but definite geothermal signature. It lies just 375 feet from the nearest road, making access straightforward.
The spring emerges in the rolling sagebrush country surrounding Blackfoot Reservoir, which covers 18,000 surface acres when full. The Aspen Range rises to the east, and the broad Blackfoot River valley stretches north. Annual snowfall hits nearly 100 inches, and average temperatures hover around 41 degrees Fahrenheit, giving the landscape a windswept, high-desert character. The warm water stands out against the generally cold surroundings, though it would not be mistaken for a soaking spring.
The Blackfoot River valley sits in a graben, a block of earth dropped between parallel faults, which is part of the greater Basin and Range extensional province. This faulting creates pathways for groundwater to circulate to moderate depths and return with modest heat. The reservoir itself was created in 1910 for irrigation, but the warm springs predate it, flowing from the same fault systems that shaped the valley.
Blackfoot Reservoir Campground sits less than 10 miles away, with 16 developed sites, 12 standard sites, boat ramps, and an RV dump station. The campground is managed by BLM and charges fees from May 15 through September 15. The spring is a short walk from the road. Bring layers, as wind across the reservoir can drop perceived temperatures sharply.
Is Blackfoot Reservoir Warm Spring worth visiting?
Best for
- Overnight camping trips
Overview Blackfoot Reservoir Campground is managed by the Bureau of Land Management (BLM) and is located on the southwest end of the Blackfoot Reservoir. The Reservoir covers 18,000 surface acres when full and is the second largest reservoir in southeastern Idaho. The campground has an annual fee season from May 15th - September 15th and is equipped with 16 fully developed campsites, 12 standard campsites, 6 day-use sites, 2 boat ramps, and an RV dump station. The site offers recreational act...