statistically, whiteness is european ancestry, more broadly being a combination of germanic, irish, french, polish, etc. It's more of a monolithic ethnic group considering how broad and consistent it seems to be amongst it's various groups, much like the term "black" is, or "african american"

Curiously, pennsylvania, isn't exactly a conglomeration of various different races, it's actually a state, which is entirely irrelevant to the people that are contained within it, interestingly enough.