For many years, the evidence was sufficiently contradictory that it could not be identified with a specific state; however, Matt Groening has come forward and admitted that it was based on Springfield, Oregon.[7] This can be questioned however, because during the couch gag at the beginning of the episode "The Ziff Who Came to Dinner", the screen pans out to the map of the United States, and the location over Illinois, and it is stated to be in southern Illinois, and there is no evidence towards it being Oregon.
The city population is estimated to be approximately 60,000. It's zip code is 80085, as of Moe Letter Blues. It is understood as a sister city to Shelbyville, which in real life would be Eugene, Oregon. The city has often been dubbed as the, or at a stretch, one of America's worst towns and called "America's Crud Bucket","The Armpit of America's Butt-Crack"[8], "The Little Town That Can't and Won't, "The World's Meanest City", as well as being the "World's Fattest Town". It is one and a half times bigger than Alaska, with West Springfield the shape of Texas.
Geographically, the city is based on Simpsonville, KY, and it is possibly where the family name "Simpson" for the show originates. Simpsonville neighbors with Shelbyville, KY. Springfield's state's capital, Capital City, is inspired by Frankfurt, KY's airport, Capital City Airport.
Founded in 1796 by Jebediah Springfield, a.k.a. Hans Sprungfeld, and a band of fiercely determined pioneers out of Maryland who set off after misinterpreting a passage in The Bible, Springfield seems to be a small city rather than a megalopolis. Its features include one nuclear power plant; at least five elementary schools; a minor league all-star baseball stadium; an airport; a harbor; a downtown district; a large tire yard (burning since 1966); a ghetto; a Russian District; its own Little Italy; several specialized shopping districts, Moe's Tavern, Barney's Bowl-A-Rama and a Chinatown.
Springfield's nearest neighboring town is Shelbyville. There is a strong rivalry between the towns, dating back to the rivalry between their founder - Jebediah Springfield and Shelbyville Manhattan. Manhattan wanted to found a city where men were free to marry their cousins, but Springfield refused to allow it, so Shelbyville was founded as a rival town.[9] The story of the dispute between Jebediah Springfield and Shelbyville Manhattan contains faint references to the historical stories of the deal between Asa Lovejoy and William Overton to file a land claim, and the dispute between Lovejoy and Francis W. Pettygrove over the name of Portland, Oregon.