2942 Trail Canyon Rd, Soda Springs, ID 83276
This preserve established by the Nature Conservancy protects crystal-clear pools and a unique wetland complex at the base of the scenic Aspen Mountains. The cold springs that feed the terraced pools and creek system deposit high concentrations of travertine (calcium carbonate), which gives the site its unique geology. Perhaps the most impressive physical feature is Formation Cave, which is almost 10 feet tall at the entrance and 200 feet long. The ponds attract numerous wintering waterfowl and support a healthy trout population. Watch for mule deer, raptors, and numerous songbirds. This site is a stop on the Pioneer Historic National Scenic Byway.