Arling Hot Spring
Arling Hot Spring surfaces at 90 degrees Fahrenheit near Cascade, Idaho, placing it on the cooler end of the thermal spectrum. Its highly alkaline water, with a pH of 9.8 and low mineral content, distinguishes it chemically from the region's hotter springs. Roadside access at 4,860 feet elevation makes it a quick stop in Valley County.
The spring sits in a mountain valley corridor west of Cascade, surrounded by mixed conifer forest typical of central Idaho's mid-elevations. At nearly 4,900 feet, winters bring over 11 feet of snow, blanketing the landscape from November through March. The sodium-dominant, soft water emerges clear with minimal dissolved solids at 218 parts per million. Nearby Lake Cascade stretches across the valley floor, visible through gaps in the ponderosa and Douglas fir.
Arling Hot Spring rises along a fault zone in the Idaho Batholith, the same massive granitic intrusion responsible for dozens of thermal features across central Idaho. The batholith formed roughly 75 to 100 million years ago, and deep-circulating groundwater heated by residual geothermal energy feeds springs throughout the region. Valley County holds one of the highest concentrations of thermal springs in the state.
The spring lies about 100 meters from the road, making access straightforward in dry months. Amanita Campground at Lake Cascade sits roughly 10 miles away and accepts reservations. Winter access depends on road conditions, as the area receives heavy snowfall. Water temperature hovers near body heat, so expect a lukewarm soak rather than a steaming pool.
Is Arling Hot Spring worth visiting?
Best for
- Warm-water soaking
- Easy day trips
- Overnight camping trips
The water at Arling Hot Spring is alkaline (pH 9.8) with 218 mg/L total dissolved solids.
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Overview Amanita Campground is located next to scenic Lake Cascade in west-central Idaho. It is near the town of Donnelly, at an elevation of 4,850 feet. Boating, fishing, swimming and hiking are popular activities in this scenic region. Recreation Lake Cascade offers excellent opportunities for boating, water skiing, canoeing, windsurfing and sailing. Anglers enjoy casting for rainbow trout, coho salmon, smallmouth bass and perch. A boat ramp is located at the neighboring Rainbow Point Campg...