Following Sorcha and Banjo Johnny...
It is, indeed, Ashoken. The tune Ashoken Farewell, used with such good effect in the Ken Burns video series on the Civil War, was written by Jay Ungar as the season closer at the music camp he runs annually in New York State (http://www.jayandmolly.com/camp.html). Later, it was incorporated into the video. The camp is one of the great traditional musical experiences of all time. Words to the tune were written by Grian McGregor, an Ashokan "camper." They're indexed in the Mudcat archive.