Were they unaffected by the Great Migrations? Is there a history of discrimination that prevented minorities from coming?
If I might expand on this question - there was a history of discrimination and strongly negative views against Franco-Americans in Maine for many years, to the point where Stephen King references the likelihood of being stabbed in a bar by a man who only speaks french in one of his early books, but I've never encountered a good primary source and would love to read more about the local behavior and attitude towards the Canadian French in Maine.