Doh! The Simpsons creator Matt Groening reveals the real Springfield is in Oregon

One of the best-kept secrets in television history has been revealed, with The Simpsons creator Matt Groening pointing to Springfield, Oregon, as the inspiration for the animated home town of Homer and family.

Groening told Smithsonian magazine that he was inspired by the television show Father Knows Best, which took place in a place called Springfield. He worked out that Springfield was one of the most common city names in the US.

"In anticipation of the success of the show, I thought, 'This will be cool; everyone will think it's their Springfield'. And they do," he said.

The series has been on the air for more than 20 years, becoming the longest-running American sitcom, the longest-running US animated programme and a cultural phenomenon.

Groening said he has long given fake answers when asked about the Simpsons' home town, leaving open the possibility that his latest one is itself another fake.

The show has made a running joke of hiding the true Springfield location. In one episode, daughter Lisa points to Springfield on a map, but the animated "camera view" is blocked by son Bart's head.

People in the real Springfield - the one in Oregon - took on the mantle of the show's hometown after Groening visited during a tour before the 2007 film The Simpsons Movie. That Springfield is 100 miles south of Groening's home town of Portland.

When Springfield community relations manager Niel Laudati was told about Groening's announcement, he said: "Oh, OK, we knew that."

The city has already incorporated the Simpsons into local lore. The Springfield Museum features a couch similar to the animated one shown in the show's opening credits, and a plaque marking the movie's release.

The Springfield depicted in The Simpsons is not always a flattering portrait. The school is falling apart, there is a constant fire at the town dump and the mayor is helplessly corrupt.

"We kind of got past it," Mr Laudati said. "We don't dwell on the bad stuff. Obviously we don't have a nuclear power plant. We don't have a lot of stuff in the Simpsons.

"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."