The show is filmed entirely on the Universal Studios back lot in Hollywood. The town square is the same central place that was used in the Back to the Future trilogy. Subsequentially, Tom Wilson, who played Biff Tannen in the trilogy, has been known to pop up now and then in the show.
The town, Grandview, was also the town in Gilmore Girls (2000), Pretty Little Liars (2010), Heart of Dixie (2011) and The Dukes of Hazzard (1979).
World-renowned psychic James Van Praagh served as a consultant during some shows in the second season.
The pilot shows a California license plate on a vehicle. Subsequent license plates, which look like they're from New York, are generic.
The stories are based in part on the work of spirit communicator Mary Ann Winkowski.
Cesar Millan (also known as the "Dog Whisperer") featured a couple of times on this show. During season one, episode sixteen, "Dead Man's Ridge", the character Andrea was twice seen reading a book written by him. Then, in season two, episode eighteen, "Children of Ghosts", Cesar makes a cameo appearance as himself.
Gus (Giancarlo Esposito) and Jesse (Aaron Paul) from Breaking Bad (2008) appeared together in season one, episode nineteen, "Fury". Mike (Jonathan Banks) also appears in this series.
Sisters Alexa PenaVega and Makenzie Vega have been on the show, but not in the same episode.
Director John Gray is from Bay Ridge, Brooklyn, New York originally, and in many of the episodes there are references to streets and locations from Bay Ridge, Brooklyn (example, Lento's Restaurant was the name of an actual Bay Ridge restaurant for over thirty years).
Both Jennifer Love Hewitt and Aisha Tyler have starred as FBI profilers on Criminal Minds.
The name of Melinda's store might be a reference to Jennifer Love Hewitt also being a singer: Melinda's shop is called "Same As It Never Was". In 1999, Jennifer Love Hewitt released a song called "How Do I Deal?", in which she sings the line "same as it ever was", a line which is also sung in the Talking Heads song, "Once In A Lifetime".
The second Touchstone (later ABC Studios) produced show not to be aired on ABC. The other two ABC Studios produced shows that are still airing on CBS are: The Amazing Race (2001) and Criminal Minds (2005).