Sulphur Creek Hot Spring
Sulphur Creek Hot Spring sits just 2.6 kilometers from Boundary Creek Campground at the gateway to the Frank Church River of No Return Wilderness. With a pH of 9.9, this is among the most alkaline thermal springs in Idaho, giving the water a slippery, almost soapy texture on skin.
The short walk of roughly 316 meters from the road leads through Valley County forest at 5,740 feet elevation. The spring emerges near its namesake creek, and the sulfur smell arrives before the water comes into view. The alkaline water feels distinctly different from neutral-pH springs, softer against the skin. Heavy snowfall, averaging 175 inches annually, buries the surrounding terrain for months and feeds the dense conifer stands that shade the approach.
Sulphur Creek's extreme alkalinity results from prolonged contact with silicate minerals deep underground, where sodium replaces calcium in solution. USGS measurements recorded temperatures around 107.6 degrees Fahrenheit. The low calcium content of just 2.1 mg/L confirms the water spends significant time in volcanic rock rather than limestone. The Frank Church Wilderness surrounding this area preserves the largest contiguous roadless area in the lower 48 states.
The spring requires only a short walk from the road. Boundary Creek Campground, 2.6 kilometers away, offers 15 sites with five reservable during the June 15 through August 15 high season. This campground primarily serves rafters launching on the Middle Fork of the Salmon, so expect a river-oriented crowd. Winter access depends on snow conditions, which can be severe above 5,700 feet.
Is Sulphur Creek Hot Spring worth visiting?
Best for
- Overnight camping trips
The water at Sulphur Creek Hot Spring is alkaline (pH 9.9).
Overview Boundary Creek Campground is located at the edge of the Frank Church River of No Return Wilderness, adjacent to the boat launch for the Middle Fork of the Salmon River in Idaho. The site generally provides overnight camping for boaters waiting to launch the next day on their permit to float the Middle Fork. Of the 15 campsites, 5 can be reserved during the high-use season (June 15-Aug. 15); the remaining 10 are first-come, first-served. Outside of those dates, all 15 sites are first-...