The speaker informs the readers that it’s very late at night in the first line. The first stanza also implies that he’s in his “chamber” at home among “many a quaint and curious volume of forgotten lore”:
Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore,—
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door.
