"The Haunted Palace" is an allegory. The palace itself represents the human mind (or rather the breakdown of the human mind). Reread the poem considering this analysis. What key words/phrases, etc. indicate that the palace is a human mind on the verge of going insane? Share your responses. Feel free to add any other questions/comments for discussion.
Check out this site for a short analysis. http://www.etsu.edu/writing/amlit1_f05/anthology/haunted.htm