No power plant, no Krusty Burger – but this is the real home of the Simpsons

From Springfield, Ohio, to the city's namesakes in West Virginia, Vermont and Illinois, one familiar exclamation resounds: "Doh!" After 23 years, the creator of The Simpsons has finally broken his silence and revealed that the real-life inspiration for the animated series is Springfield in Oregon.

One of the best-kept secrets in television history was finally spilled by Matt Groening when he disclosed that the model for his fictional city of corrupt politicians, idiot cops and lovably dysfunctional families was the Springfield in the Pacific North-west state.

The location of the longest-running sitcom in the US had been a recurring joke on the show. In one episode, Lisa Simpson points to Springfield on a map, but the camera view is blocked by her brother Bart's head. False clues inserted by Groening prompted several of America's 38 Springfields to claim to be the "real" home of Homer Simpson.

Now Groening has revealed that he always had in mind the Springfield 100 miles south of his home town of Portland, Oregon. "Springfield was named after Springfield, Oregon," Groening, 58, told The Smithsonian. "The only reason is that when I was a kid, the TV show Father Knows Best took place in the town of Springfield, and I was thrilled because I imagined that it was the town next to Portland, my hometown."

The cartoonist also knew that Springfield was a common city name in the US, giving his fictional creation an everyman quality. "In anticipation of the success of the show, I thought, 'this will be cool; everyone will think it's their Springfield'," he said. "And they do."

Asked why he had refused to identify his inspiration until now, he added: "I don't want to ruin it for people, you know? Whenever people say it's Springfield, Ohio, or Springfield, Massachusetts, or Springfield, wherever, I always go 'yup, that's right'."

The denizens of Springfield, Oregon's ninth-largest city with a population of 60,000, adopted a blasé attitude to the revelation. "Oh OK, we knew that," Niel Laudati, the city's community-relations manager, said.

The animated Springfield is not always a flattering portrayal of American values. "We don't dwell on the bad stuff," Mr Laudati said. "Obviously we don't have a nuclear power plant. What we do have are a lot of blue-collar working families that go to church every week and eat dinner together. That is accurate."

The signs were always there, locals said. The downtown district houses a statue of an unnamed man astride a horse, just as the fictional Springfield features a memorial to founder Jebediah Springfield.

The Springfield city council website announced the news: "Simpson creator reveals this is the REAL Springfield in Smithsonian Magazine... although he also told us in 2007."

Groening visited the city on a tour before the release of the 2007 film The Simpsons Movie and signed a plaque: "Yo to Springfield, Oregon – the real Springfield!". But he admitted saying that to all the Springfields.