The Pennsylvania Dutch came from Germany, actually.
It was one of those funny language misunderstandings.
When asked what nationality they were, the new settlers said “Deutsch.”
Americans were never very good with languages. And although it was a misunderstanding, the name stuck.
Many Pennsylvania Dutch are descendants of refugees from the Palatinate of the German Rhine, where French expansionism forced them to flee.
Several conflicts resulted in the emigration, including the War of the Grand Alliance from 1689 to 1697, which started it all.