The film's UK release, scheduled for 28 December 2007, has been postponed indefinitely because of the film's similarity to the real-life case of four-year-old Madeleine McCann who disappeared from the holiday apartment where she and her family were staying in Praia da Luz, Portugal, on 3 May 2007.
Broadway actress Amy Ryan looked and sounded so convincing as a low class Dorchester mom that a security guard mistook her for a fan on the first day of location filming, and wouldn't let her on the set. One of the producers finally noticed her on the other side of one of the barricades, and said she should be let through. The incident made Ryan twenty minutes late, but convinced her the Boston accent she'd prepared was realistic.
Amy Ryan was so convincing with her Boston accent in her audition, that director Ben Affleck asked her what part of Boston she was from
According to the DVD commentary, the flyover shot of the quarry is a special effects shot, since the quarry actually had no water.