Penny Hot Springs is a beloved free, primitive soak tucked along the banks of the Crystal River in the mountains just south of Carbondale, Colorado — an easy roadside stop on the scenic drive between Carbondale and Redstone, not far from Aspen and Snowmass. With hot mineral water rising right at the river's edge and dramatic canyon walls all around, it's one of the most accessible wild hot springs in the Roaring Fork Valley.

The setup is wonderfully simple. Soakers have stacked river rocks into low walls to form pools along the bank, trapping the hot geothermal water (which emerges scalding, around 130 degrees) and letting in just enough cold river water to dial in the perfect temperature — you can even rearrange the rocks to make your pool hotter or cooler. The main pool is roughly 20 feet across and holds about ten people, with the cold, clear Crystal River rushing by right beside you, a hot-and-cold contrast that's pure mountain magic.

Getting there couldn't be easier: a large parking area sits on the east side of Highway 133 near mile marker 55, and a short, steep path leads down to the river and the pools. It's free, with no permit required.

One important timing note: during spring snowmelt the Crystal River runs high and can push into the pools or wash them out entirely, dropping the temperature fast. The best and safest times to soak are summer, fall, and winter, when the river is lower. A few other tips: it's a clothing-optional spot by tradition, so gauge the scene if you've brought the family; test the water before getting in (the source is very hot); wear sandals for the rocky bank; and pack out everything to keep this free gem clean. Easy, scenic, and free, Penny Hot Springs is a quintessential Colorado roadside soak.