DNA Origins-This map shows the expansion of Celtic tribes by 275 A. (in light green) from their presumed origin, the Bronze Age Hallstatt culture (in yellow). Dark green areas show regions where Celtic languages are still spoken today.
Irish Immigration: In 1840 America saw a dramatic increase in irish immigration due to the potato famine in Ireland. Their immigration led to settlement in eastern cities like New York and Boston. This also led to competition for jobs.