I'm Scottish and when I think of folk music the US never springs to mind.Although Guthrie,and Seeger etc are considered folk music in America I think of them more as protest singers I am in no way being derogotary of American folk music by saying this it is just that my perception of what folk music is is different.I generally think of music and songs that have been passed down for centuries through the people of a nation like the Orain luaidh(waulking songs),Muckle sangs or piobaireachd of Scotland or Sean Nos of Ireland or contemporary music that closely emulates it.