The White Pilgrim was Joseph Thomas, a 'New Light Christian' evangelist who dressed in white raiment and traveled through much of the area east of the Mississippi from July 6, 1815, to April 9, 1835, when he died of the smallpox in Johnsonburg, New Jersey. In the fall of 1838, a fellow preacher, Elder John Ellis of Dayton, Ohio, visited the grave of the Pilgrim and composed the poem which the author said was 'sung around the world.' At any rate, the song appeared in various shape-note hymnals and on at least one broadside, gained three stanzas in its various appearances, and has been collected by folklorists from Vermont to California... In some Northern hymn books, including those edited by Elder Ellis, the text is set to 'Lily Dale', but the more popular tune is the one Doc sings, a set of 'The Braes of Balquhidder'...."
http://expectingrain.com/dok/who/p/pilgrimlone.html