Director Trademark (M. Night Shyamalan): [reflection] The first time we see the psychiatrist talking to Ethan, we do through his reflection on the glass table.
Uncredited, actor Ryan Robbins appears in a photograph as the male secret service agent Burke is searching for.
The sheriff's unhelpful secretary (Arlene Moran) has the same last name as the sheriff's receptionist in the TV show Twin Peaks (Lucy Moran).