From the PFBC website:
Class A streams
"Streams that support a population of wild (natural reproduction) trout of sufficient size and abundance to support a long-term and rewarding sport fishery. The Commission does not stock these streams."
Wilderness Trout Streams:
"Wilderness trout stream management is based upon the provision of a wild trout fishing experience in a remote, natural and unspoiled environment where man's disruptive activities are minimized."
Several Class A streams in Fayette, Somerset and Westmoreland Counties. Several WT streams in Westmoreland and Somerset, and maybe one or two in Fayette.
I've fished a handful in Westmoreland for wild brook trout.