The Washington Department of Fish and Wildlife's website features a comprehesive guide to fishing the states's high elevation lakes.
Created by colliding tectonic plates, and carved by glaciers and ice, high mountain lakes in Washington offer anglers a recreational experience unmatched by any other waters in the state. The fishing is spectacular in these high elevation gems but the experience is punctuated by fantastic camping, hiking, wildlife watching and the scenic vistas taken in during your stay, and travels to and from these unique angling opportunities. Without a doubt, high lakes trout fishing is one of Washington's premier recreational opportunities.
LINK (via: WDFW)