The film was given an R rating by the MPAA. The filmmakers had thought the final cut had a chance of getting the more-box office friendly PG-13 rating and asked the ratings board for clarification. The MPAA said simply that the film was so scary that there were no cuts or edits possible that would make it a viable PG-13 film; the filmmakers did not want to alter the film's tone and accepted the R-rating without any appeals.
The real Bathsheba Sherman was suspected of witchcraft and of killing an infant child, but her name was legally cleared after being found not guilty by a court of law. She died of natural causes in 1885, not by hanging as the movie portrays. She is buried in Harrisville, RI.
When Roger is investigating the source of the banging sound and sees the door to the kitchen creak open, it is opened nearly all the way. In the next shot as he is approaching it, it is nearly closed.
During the tape recorder scene, the balance, tone and volume controls of the recorder change positions midway through the scene, although none of the characters are shown to adjust them.