Trivia: Betty Buckley really slapped Nancy Allen across the face during the detention scene. Brian DePalma wanted the right reaction.
Trivia: Frank Wills, the security guard who discovered the Watergate break-in, plays himself.
Trivia: The train crash at the end of the movie was filmed at Toronto's Union Station. While the layout of Union Station is irrelevant, it's interesting that the train's final position would have required it to cross the tracks at a 90° angle (more or less) and drop down onto the ramp that connects the Great Hall to the passenger departure area.
Trivia: The smile that Damien gives at the very end wasn't scripted. Originally, Damien was supposed to "look really mean," but Harvey Stephens couldn't keep a straight face: he started to smile, then laugh. Richard Donner decided that the smile made Damien look even more evil, so it stayed in the movie.
Trivia: The assault takes place on Precinct 9, Division 13. There is no "Precinct 13" in the film. At first John Carpenter wanted to call the film "The Anderson Alamo" (the original title of his screenplay), and at one point he changed the working title to "The Siege." CKK, the film's distributor, was responsible for the misnomer; it rejected Carpenter's titles and came up with the name "Assault on Precinct 13" (which it felt was more ominous sounding) during post-production.
Trivia: Alfred Hitchcock's silhouette can be seen in the window of the registry of births and deaths office. He is the figure on the right pointing at the figure on the left.
Trivia: In the film two hoods are called "Lalo" and "Buchinski". "Lalo" is a reference to Lalo Schifrin, composer of the other "Dirty Harry" movie soundtracks. "Buchinski" was the real last name of the actor Charles Bronson.