Question: where did you sleep last night folk song
Answer: `` In the Pines '' , also known as `` Where Did You Sleep Last Night ? '' and `` Black Girl '' , is a traditional American folk song originating from two songs , `` In the Pines '' and `` The Longest Train '' , both of which whose authorship is unknown and date back to at least the 1870s ( though some contend an older , Irish history ) .