Young has never said who the Cinnamon Girl is. He prefers to leave lyric interpretations to the listener.
This song got Young in trouble with his wife. He had to explain that the Cinnamon Girl was just a person he came across while touring.
Young recorded this with his band Crazy Horse.
This was originally released on the album in 1969. Young put out an alternate version as a single in 1970, which did well partly because…
I wanna live with a cinnamon girl
I could be happy the rest of my life
With a cinnamon girl