I went camping with my girlfriend and her family this summer at Timothy Lake. There were some amazing
places to swim up there. We found this little nook off the main lake with a man-made fire pit, looked like it had been there a hundred years. Beautiful! We fully intended to camp there, but then my girlfriend's brother punched this guy in the face, and he had cancer, and it was a whole debacle. There was alcohol involved. But don't let that change your mind. Trust me on this one. Timothy Lake.
It's near Estacada, off of Hwy 26.
Timothy Lake @ Wikipedia