Indeed. My grandfather used to tell me tales of his day in the Civilian Conservation Corps, building roads in the southern end of the Appalachian Mountains in the 1930s.

They'd be going along clearing out land for a road and they'd come across a hollow with residents who had been isolated for decades, if not a century or more. He said they knew nothing about the world at all, though they would have basic tools from way back. Of course, that was 80 years ago now.