Hot Springs in Colorado

Conundrum Hot Springs near Aspen is Colorado's marquee wild soak. Sitting at 11,200 feet in the Maroon Bells-Snowmass Wilderness, the pools require an 8.5-mile hike gaining over 2,500 feet of elevation. A permit is required; book well in advance, as slots fill quickly. The access window is limited to summer and early fall; snow closes the trail by mid-October most years, and alpine weather can turn dangerous fast even in August.

Colorado's geothermal heat follows the deep faults that formed the Rockies. Water circulates far underground, picks up heat and minerals, then surfaces through fractures in the ancient rock. Mineral content varies from nearly pure to heavy sulfur and iron.