It was apparently written by Irish musician Shaun O'Nolan and popularised by another Irish musician Mick Moloney. I don't see a source for the year and location of it's authoring. Maybe you could provide one?

And audiences in America isn't the same thing as American audiences. There was and still is a very large Irish diaspora in the United States. I'd also appreciate a source for the claim that it was intentionally written for American audiences.