Here are some facts/reviews about "Where Did You Sleep Last Night?" from Wikipedia :
"In the Pines", also known as "Black Girl" and "Where Did You Sleep Last Night?", is a traditional American folk song which dates back to at least the 1870s, and is believed to be Southern Appalachian in origin. The identity of the song's author is unknown, but it has been recorded by dozens of artists in numerous genres. A 1993 acoustic version by Nirvana introduced the song to many people at the end of the twentieth century. Kurt Cobain attributed authorship to Lead Belly, who had recorded the song several times, beginning in 1944, but the version performed by Lead Belly and covered by Nirvana does not differ substantially from other variants of the song. Most versions of this song are performed in 6/8 time.
Like numerous other folk songs, "Where Did You Sleep Last Night" was passed on from one generation and locale to the next by word of mouth. The first printed version of the song, compiled by Cecil Sharp, appeared in 1917, and comprised just four lines and a melody. The lines are:
Black girl, black girl, don't lie to me
Where did you stay last night?
I stayed in the pines where the sun never shines
And shivered when the cold wind blows
In 1925, a version of the song was recorded onto phonograph cylinder by a folk collector. This was the first documentation of "The Longest Train" variant of the song. This variant include a stanza about "The longest train I ever saw". "The Longest Train" stanzas probably began as a separate song that later merged into "Where Did You Sleep Last Night". Lyrics in some versions about "Joe Brown's coal mine" and "the Georgia line" may date it to Joseph E. Brown, a former Governor of Georgia, who famously leased convicts to operate coal mines in the 1870s. While early renditions that mention that someone's "head was found in the driver's wheel" make clear that the train caused the decapitation, some later versions would drop the reference to the train and reattribute the cause. Music historian Norm Cohen, in his 1981 book "Long Steel Rail: The Railroad in American Folksong," states the song came to consist of three frequent elements: a chorus about "in the pines", a stanza about "the longest train" and a stanza about a decapitation, though not all elements are present in all versions.
Starting the year following the 1925 recording, commercial recordings of the song were done by various folk and bluegrass bands. In a 1970 dissertation, Judith McCulloh found 160 permutations of the song. As well as rearrangement of the three frequent elements, the person who goes into the pines or who is decapitated has been described as a man, a woman, an adolescent, a wife, a husband or a parent, while the pines have represented sexuality, death or loneliness. The train has been described killing a loved one, as taking one's beloved away or as leaving an itinerant worker far from home.
In variants in which the song describes a confrontation, the person being challenged is always a woman, and never a man. The Kossoy Sisters folk version asks, "Little girl, little girl, where'd you stay last night? Not even your mother knows." The reply to one version's "Where did you get that dress, and those shoes that are so fine?" is "from a man in the mines, who sleeps in the pines." The theme of a woman who has been caught doing something she should not is thus also common to many variants. One variant, sang in the early twentieth century by the Ellison clan (Ora Ellison, deceased) in Lookout Mountain Georgia, told of the rape of a young Georgia girl, who fled to the pines in shame. Her rapist, a male soldier, was later beheaded by the train. Mrs. Ellison had stated that it was her belief that the song was from the time shortly after the U.S. Civil War.