"On Top of Old Smokey" is one of the songs recorded by The Weavers using Pete Seeger's arrangement. In his book, American Favorite Ballads, Seeger says that he learned it from someone in the Smokey Mountains. It was also recorded by Burl Ives and others. It has since become known everywhere. It's hard to get anyone to take this song seriously anymore. It's still a good sing-along song.
A variant of this tune is used for "Little Mohee" which is also in this section.
I don't know where or when I learned this. Like most people, I've known it forever.