Boulder Hot Springs, Boulder, Montana

Boulder Hot Springs Inn, Spa and Retreat Center occupies nearly 300 acres of meadows, wetlands and forest in Peace Valley at 31 Hot Springs Road outside Boulder, Montana, in the foothills of the Elkhorn Mountains. The operator presents a historic inn and spa whose main draw is mineral geothermal water, with spa services, bed-and-breakfast and guest rooms, and retreat space. The property markets itself as an alcohol-, drug- and smoke-free sanctuary (smoking outdoors only if at least twenty feet from the building per the FAQ). Day use for the spa and springs is listed every day from 10 a.m. to 8 p.m. Overnight guests get breakfast; other meals are oriented to retreat groups or parties of about ten or more, with snacks at the front desk and more options three miles away in the town of Boulder. The FAQ states the inn is not a licensed public campground. Service dogs are allowed under posted rules; family pets are not. NOAA’s thermal springs survey recorded a nearby vent near 169°F; pool temperatures on site are managed for soaking and may differ from the vent reading.

Sources: boulderhotsprings.com (1), boulderhotsprings.com (2)

Boulder Hot Springs, in Montana, is within a quarter mile of Hot Springs Road. Not a backcountry pool — developed resort or spa, on the operator's own site. Vent heat in the NOAA thermal springs survey: 169°F, scalding. Entry falls in the $$$ price band and amenities on file include lodging on-site, showers, massage/spa and restrooms. Nothing establishes swimsuit requirements for this listing yet.

Source: NOAA thermal springs survey — BOULDER HOT SPRINGS, 0.13 mi