Cougar Hot Springs
Also known as Terwilliger Hot Springs.
Located at the Cougar resovoir (hence the name), in Rainbow, OR this is the most popular hot spring in the Eugene area. It's now a fee based spring, but the costs are $3.00 per person.
The source is the top pool which is around 112° F. There are several pools below this which get cooler they descend to a swimming hole. Most of the pools have bedrock with some gravel and sand at the bottom.
The hot springs are day use only.
$3.00 per person.
Rider Creek Arm of Cougar Reservoir and Terwilliger Hot Springs are 53.3 miles East of Eugene. From the intersection of I-5 and I-105/Highway 126 in Eugene, head east on Highway 126 to the end of the divided highway, 6.6 miles. Turn left onto Main Street, continuing on Highway 126, and drive to the Cougar Reservoir turnoff, Forest Road 19, 39.0 miles, between mileposts 45 and 46. Turn right and drive to a dam, 3.4 miles. Turn right at the dam to go around the west side of the reservoir to the parking lot near the hot springs trailhead, 4.3 miles.
From La Pine:
Head North on US-97 to US-20 (32 mi), then head west toward Salem (48 mi). Merge onto OR-126 and head east for 28.1 miles to Rainbow. Turn left onto the Mckenzie River Rd. Follow the signs.