The title of the episode, "Acheron", refers to one of the rivers of the underworld within Greek mythology, which was known as the "river of woe".
Almost every photo on the Commonwealth's "Wall of the Lost" came from the show's crew members.
In the comics, Michonne is the one who finds a picture of herself on the Commonwealth's wall.
When the group's walking through a rainstorm, the special effects team heated the water so the cast wouldn't catch a cold.
During the destruction of Alexandria, the Whispers decided to edit the "Silence the Whispers" graffiti that Dante had painted last season. "Whispers into Screams" is also the title for Volume 23 of the graphic novel.