@izzythepush,
Like the italian immigrants, irish immigrants also moved around.
Me, I think of SF Bay area italians as way different than those in New Jersey.
Don't trust me, of course. I'm no sociologist (shoulda thought of that).
My family is mixed irish am - from my mother's side, all Boston, even the ones who moved to LA in the early 1900's; on my father's side, looks like from NY entry to a variety of places as a lawyer, including Idaho (silver?) and California (hop farm?), and eventually me. Both sides from Mayo.
Anyway, a lot of that stuff came from the east, far as I discern. (no data)