Flyfishing only lakes and rivers

i am planning a trip to a flyfishing only lake or river in the area of below mayfeild lake and east of i - 5 and north of oregon
if you know of any good spots please email them to me and if the is a lake really close to a river that would be terrific :BIGSMILE thanks ,
Later in the spring try Merrill Lake or Coldwater up at Mt. St Helens. There are numerous opportunities for river fishing in the area (Toutle, Green, Lewis system) after June 1 for Steelies.
Both Merrill and Coldwater are larger lakes with some nice fish in them. Dragging around buggers is an easy and effective way to fish them.

Go Cougars!!