They shut it down (IIRC) when they were bought out. It's probably like all the other big (and micro) brewers. I think they now make Iron City at the Rolling Rock plant in Latrobe. Sam Adams does the same kind of thing.
Sam actually started out being brewed in Pittsburgh, but they took over an old boston brewery site, I think (Hafenrefer, IIRC) and do at least some up in Boston. Given their variety, it wouldn't surprise me if some of their small runs are brewed remotely.