[pj3000]

Similarly to Boston, Pittsburgh/SW Pennsylvania Irish originate from all over the "Emerald Isle".

Irish Protestants from Ulster northern Ireland (counties Antrim, Donegal, Tyrone, Armagh, Down, Derry...) made up the early wave of colonial Irish immigrants in the late 1700s and settled throughout southwestern PA. Then Irish Catholics from all over the island came from the 1820s on, and turned an historically Protestant city into a Catholic one, similarly to what occurred in Boston, NY, Philadelphia, Baltimore. Though the region surrounding Pittsburgh was already "Scots-Irish" Protestant by the time Pittsburgh Irish Protestants fled to the hinterlands, since those areas were already populated by Scots-Irish settlers who moved to the frontier from the aforementioned cities.