I've been told they are in Dexter and Dorena. I think they are in the Willamette too. My wife has a friend that hangs out at the naked gay beach and he said they catch smallie's there in the summer so if they are in there then I'd think they'd be in the coast fork of the willamette also.
the coast fork of the willamette is where you're gonna find tons of 'em, i was fishing for trout one day up on the coastal fork and i ran into 3 nice smallies, biggest one was about 1 1/2 lbs.