Joni Mitchell composed the song based on what she had heard from her then-boyfriend Graham Nash about the Woodstock Music and Art Festival. She had not been there herself, since a manager had told her that it would, instead, be more advantageous for her to appear on "The Dick Cavett Show". She composed it in a hotel room in New York City, watching televised reports of the festival. "The deprivation of not being able to go provided me with an intense angle on Woodstock," she told an interviewer shortly after the event. David Crosby, interviewed for the documentary "Joni Mitchell: Woman of Heart and Mind," stated that Mitchell had captured the feeling and importance of the Woodstock festival better than anyone who had actually been there.