Several characters in prison have the number 24601. That same prisoner number was Jean Valjean's in Victor Hugo's 19th-century novel Les Misérables.
The character "Krusty the Clown" was inspired by a real-life TV kiddie show host named 'Rusty Nails' and Dan Castellaneta's voice characterization was based on Chicago television legend Bob Bell (IV) who portrayed WGN-TV's Bozo from 1960-1984.
The French version of the TV show translated "D'oh" into "T'oh."
Bart Simpson was ranked #1 in TV Guide's list of "TV's 10 Biggest Brats" (27 March 2005 issue).
Homer works in sector 7-G in the power plant
Bart's retort "Eat my shorts!" was ranked #3 in TV Guide's list of "TV's 20 Top Catchphrases" (21-27 August 2005 issue).
The motto for The Springfield Penitentiary is "If you committed murder, you'd be home by now!"
"Comic Book Guy's" real name is "Jeff Albertson". After being anonymous for many seasons, the creators thought it would be funny to give him the most conventional name they could think of.
Fat Tony's name was variously given as William "Fat Tony" Williams in "Bart the Murderer", as Anthony "Fat Tony" Balducci in the episode where Homer is a boxer, and as Anthony "Fat Tony" d'Amico in others. In the Episode where Krusty meets his estranged daughter, Fat Tony's middle name is revealed to be Merian
Milhouse's middle name is Mussolini.
The map of Springfield located in the Police Station shows the city is shaped almost exactly like medieval Constantinople, complete with a large road in almost the same position as the Mese, the main road of Constantinople.
In the episode "Behind the Scenes", the narrator announces "this Kentuckian family...", so with this information, Springfield is generally thought to be in Kentucky. However, the narrator was indicating that the family originally came from Kentucky, but that is not where they live currently.
Homer (Dan Castellaneta) is the only character to have dialogue in every episode. Marge (Julie Kavner) and Lisa (Yeardley Smith) have also appeared in every episode, but Marge did not deliver any dialogue in the episode 'Krusty Gets Kancelled', while Lisa did not deliver any dialogue in the episode 'Chief of Hearts'. Bart ('Nancy Cartwright') did not appear in the episode 'Four Great Women and a Manicure'.
In the episode when Lisa is elected president of Springfield Elementary she gives her email address as smartgirl63_\\\\\\\\\\\\\\\\@yahoo.com (she says it as: smart girl six three underscore backslash at Yahoo dot com)
Homer's e-mail address is ChunkyLover53@aol.com
Krusty the Klown's real name is revealed as Herschel Schmoikel Krustofski and Herschel Pinkus Yerucham Krustofski in different episodes.
Carl's last name is Carlson (BABF12) and Lenny's last name is Leonard (EABF14). The sarcastic moustached guy's name is Raphael (CABF10). Krusty the Clown's real name is Herschel Shmoikel Krustofski (8F05). The Bumblebee Man's name is Pedro (3F10). Judge Snyder's first name is Roy (CABF22). Sideshow Bob's name is Robert Underdunk Terwilliger (2F02). Comic Book Guy's real name is Jeff Albertson (GABF02).