"Oh My Darling, Clementine" is an American folk ballad usually credited to Percy Montrose (1884), although it is sometimes credited to Barker Bradford. The song is believed to have been based on another song called "Down by the River Liv'd a Maiden" by H. S. Thompson (1863).
This is one of those songs that has passed into use as a children's song and no one takes it seriously any more.
It is printed in Pete Seeger's American Favorite Ballads.