Terwilliger Hot Springs is a well-maintained, natural-feeling hot springs near Cougar Reservoir along the Mackenzie River. The hot water that feeds the springs flows from a cave source at the top of six tiered pools. As a result, each successive pool is slightly cooler in temperature than the one above it. A nearby stream also helps cool the hot water, giving visitors plenty of options for their soaking experience.
The hot springs are a 1/4-mile hike from the parking lot at Cougar Reservoir. The trail is relatively flat and well kept. You'll have a great view of Rider Creek Waterfall at the trailhead, where it spills into a pond along the edge of the reservoir. Your short hike will take you through mossy old-growth forest, and the steam of the pools is quickly visible after a few twists and turns.
There are two restrooms/changing facilities that are as moss-covered as the surrounding trees. There is also a covered shelf area to store clothing, shoes, bags and gear that is visible from the pools.
Be careful moving in and around the pools, as the rocks can be slippery due to the moisture in the air.
Clothing is optional at the hot springs (but required at the trailhead and along the trail), and it's common to find bathers making full use of this freedom. No alcohol or glass is allowed at the springs. The cost to visit the pools is $6 per person, which can be paid to the attendant at the trailhead.
Note that the pools are drained and cleaned weekly by volunteers who maintain the site. The cleaning usually occurs on Thursday mornings before 11 a.m. Please be aware the pools may not be available at this time. The pools take roughly an hour to refill after cleaning.