Allegheny county as liberal? That is, at best, a stretch. If anything Allegheny is a populist haven just as with most of western PA. Except for possibly Erie I can see no place in Western PA being shaded fully liberal. All of the more Democratic counties, along with a good number of Republican ones, are Populist. In my opinion I would be hard pressed to find a fully liberal area out west, except for some areas of inner-city Pittsburgh. People have to remember that Allegheny county is much more than just Pittsburgh proper.
This is pretty much true. But there are some very liberal areas of Pittsburgh like Oakland that are just as liberal as parts of Philadelphia.