The Harry Smith Anthology of American Folk Music is one of the most influential collections of songs on the planet. Originally released in 1952 on 6 LP records, it is now available on a 6 CD set. Dave Van Ronk wrote that "without the Harry Smith Anthology we could not have existed, because there was no other way for us to get hold of that material."
The songs on this anthology were all recorded in the 1920s and 1930s. You can easily hear an example of musical borrowing by playing The Bentley Boys 1929 "Down on Penny's Farm" next to Bob Dylan's very early (1961) "Hard Times in New York Town." Anyway, this map is an attempt to show "the geographical origin of each cut on Harry Smith's 1952 Anthology." It appears on the site of The Celestial Monochord - Journal of the Institute for Astrophysics and the Hillbilly Blues.