The local "castle" on the map is Fort Duquesne, which is listed as "ruins" but in fact has no ruins to visit. It says "The site of both forts is now occupied by Point State Park, where the outlines of the two forts have been laid in granite slabs" - which is true, but...there are no ruins here!

If forts count as castles, at least do Fort Pitt, which has the blockhouse functional.

Anyways - this is a fun project and it should continue!