SPRINGFIELD, Oregon (AP) ― 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 hometown of Homer and his dysfunctional family.

Groening told Smithsonian magazine, published online Tuesday, that he was inspired by the television show “Father Knows Best,” which took place in a place called Springfield. Springfield, Oregon, is 100 miles (160 kilometers) south of Groening’s hometown of Portland.

“When I grew up, I realized it was just a fictitious name,” Groening told the magazine. “I also figured out that Springfield was one of the most common names for a city in the U.S.

“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.

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

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

The series has been on the air for 22 years, becoming the longest-running American sitcom, the longest-running American animated program and a cultural phenomenon with colleges devoting courses to studying it.

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.”

Back then, tiny Springfield, Vermont, beat out 13 other like-named cities, including the one in Oregon, to host the movie premiere. The cities submitted videos meant to connect themselves to the fictional Springfield.

When Springfield, Oregon, 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 its own town 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.

“Yo to Springfield, Oregon ― the real Springfield!” Groening wrote. “Your pal, Matt Groening proud Oregonian!”

The Springfield depicted in “The Simpsons” isn’t always a flattering portrait. The school is falling apart, there’s a constant fire at the town dump, and Mayor Quimby is chronically, helplessly corrupt.

“We kind of got past it,” 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,” Laudati said. “That is accurate.”