Westslope cutthroat are stocked in lakes on the east side of the mountains and coastal cutts are stocked in lakes on the west side (their native drainages). The only west side exceptions are Skamania and most of Lewis counties where the cutthroat being stocked are westslope.
The eggs for the westslope cutts are taken from Twin Lakes near Lake Wenatchee. These fish are well adapted to mountain lakes, and that can be a problem. If there is any spawning habitat available at all they’ll take advantage of it. Consequently, we have lots and lots of lakes on the west side of the crest that are full of westslope cutts. Mostly too full.
If you want to catch westslope cutts, high lakes are a great place to do it.