Where I grew up in western PA, there were a number of small coal towns dotting the map where groups of eastern europeans were herded directly from Ellis Island and sent into the mines. As late as the 1980's, you could find second or even third generation folks in these towns speaking with eastern european accents.
The Melungeons are particularly fascinating because the lack of concensus on where even the name comes from opens up a whole lot of possibilities that if proven, could force a significant rewrite of some of our history.