I've been going to the Bagby Hotsprings ever since I moved to Oregon - honestly I think its one of the most enchanting places I've ever been to around the world. You drive out on logging roads up Mt Hood, then park and walk a little over a mile thru old growth forests on a well maintained trail that follows along a beautiful river (there are two amazing bridges you cross).
Once you are seriously out in the middle of now-where you come upon the Bagby Station which basically is an 100+year old log cabin and shed, a bathhouse. There are private bath tub rooms (each with a bench and posts to hold your bags and clothes and a hollowed out old tree to fill and soak in) as well as a more public space with long tubs and round tubs (the round tubs hold up to 5 or 6 people). There is another round tub down the trail past the log cabins and a few out houses for potty use. The buildings have so much character and there is steam coming up from the natural hotspring water... the trees are all dripping with moss and the steam makes the air sort of misty and mystical.
Mt Hood hotspings water contains natural lithium and other wonderful stuff to soak in. The water is very soothing and good for the body/mind/soul.
Its just incredible to experience Bagby. I swear it feels like some sort of hidden secret world, walking thru old growth forests and then finding this old well loved hot springs location. I love hot springs and I have enjoyed different natural springs around the world. This particular spring is above and beyond. Although it is getting more and more popular - so I wouldn't recommend going on the weekend.
Now adays its really safe (the forest service patrols the parking lot and volunteers maintain the station) - when I first starting going there I used to see a lot of broken glass in the parking lot (from vandalized cars) and this sorta freaked me out, but now 10 years later its really different. In fact, I found this great video about how its been cleaned up: