The character of Tia in the flashback sequences was played by Kim Richards' real-life younger sister Kyle Richards.
Kim Richards and Ike Eisenmann, who play the children in this movie and in Return from Witch Mountain (1978), appeared in a scene in Race to Witch Mountain (2009). Eisenmann is "Sheriff Antony" in the bar, and Richards is "Tina" the waitress. In this movie and its 1978 sequel, their names were similar: "Tony" and "Tia", respectively.
Bruno the Bear was only alert for about ten minutes a day, which the production crew had to carefully schedule with the children's two-hour work schedule.
At one point during the fight scene between Tony and Truck, Dermott Downs punched the bat so hard, it hit Ike Eisenmann. In some scenes, despite the Make-up Department's best efforts, you can see a greenish bruise under his left eye.
Kim Richards (Tia) had a particular affection for Bruno The Bear. One day she asked to help bathe him and, acting uncharacteristically, the bear picked her up, swung and shook her vigorously before his handler finally got Bruno to set her down. Richards was terrified, but tried to play it off for the group of spectators which had gathered.
The rarest piece of merchandising for this movie is the "Witch Mountain Flyer", a Frisbee adorned with the movie's title and an image of a spaceship.
Eddie Albert reprized his role of Jason O'Day from this movie in the 1982 failed television pilot/sequel Disneyland: Beyond Witch Mountain (1982), the only actor to do so.
Knowing that it was an integral part of the story, Ike Eisenmann (Tony) bought a harmonica and taught himself to play it, unaware that he would be dubbed in the end by professional harmonica player Tommy Morgan.
The primary cat who portrayed Winky was temperamental and difficult with which to work, particularly for Ike Eisenmann (Tony), who sustained numerous cuts and scratches from the feline.
Ike Eisenmann (Tony) and Kim Richards (Tia) first met at a screentest for this movie, and Eisenmann quickly became convinced that they'd both be cast because they looked like siblings. In addition to appearing together in the three theatrical "Witch Mountain" movies, they also played brother and sister in the CBS movie-of-the-week Devil Dog: The Hound of Hell (1978).
The Pine Woods Orphanage was actually Peninsula School of Creative Education in Menlo Park, California. The secluded sixty-room mansion was built in 1880 and converted into a school in 1925. There are countless stories of hauntings in the mansion, which were played up in the original press materials for this movie.
Final theatrical movie of Reta Shaw (Mrs. Grindley).
The geographical structure which portrayed "Witch Mountain" was a Santa Lucia Mountain in the Santa Lucia Range in Big Sur, Monterey County on the central coast of California. Candidates for a real-life Witch Mountain would be mysterious places like Silbury Hill or Mount Shasta.
The make and model of the motorhome that flew through the air was a Winnebago, specifically a 1974 Dodge Minnie Winnie Winnebago Class "C" (B-300).
This movie was released seven years afters its source novel of the same name by Alexander Key was published.
Disney Records released an audio adaptation of this movie with an eleven-page storybook. The album was narrated by Eddie Albert (Jason O'Day) and featured audio excerpts from this movie, as well as Johnny Mandel's musical score.
Disney was looking to reinvent itself after the death of founder Walt, and wanted this movie to be dark and edgy. Director John Hough got the job as a result of his work on The Legend of Hell House (1973), which Disney executives had screened.
Although the bulk of the music was composed specifically for this movie by Johnny Mandel, "Skipping Along", the track that plays when the toys come to life in the playroom, was a pre-existing piece of music by Richard Hayman. As a result of music rights issues, the entire scene was cut from some early home video editions.
The marionettes from the playroom sequence continue to be used for performances at the Bob Baker Marionette Theater, which has been designated as a historic landmark in Los Angeles, California.
This movie was re-released in the U.S. on a double bill with a re-issue of Disney's Cinderella (1950).
The name of the mysterious item that Tia carried around, which contained a map, was a "star case". Tia's star case, which housed the map to Witch Mountain, had an additional purpose in the novel. In Key's novel, Tia was mute (but communicated telepathically with Tony) and carried pencils and paper in the star case to write notes to people.
This movie included a three million dollar replica of a Byzantine castle, built between 1926 and 1934 from lava rock from Mt. Vesuvius and materials all over Europe, which served as Aristotle Bolt's (Ray Milland's) kingly abode, Xanthus.
The make and model of the chopper, which was seen flying upside down and landed that way, was a red-and-white Hughes 369HS helicopter with the branding of "Aristotle Bolt", which was the name Ray Milland's character in this movie.
Debut theatrical movie produced by Jerome Courtland, who previously had only produced in television.
Big Sur River Inn is featured in this movie under a different name.
In one scene, Tony and Tia go on an outing to see the movie Snow White and the Seven Dwarfs (1937).
Although the interiors and exteriors of Mr. Bolt's (Ray Milland's) mansion were predominantly the same location, the playroom was built on a Disney soundstage to accommodate the special effects team.