Credit: Fox Broadcasting Co/AP Photo.

After keeping fans in the dark for nearly 25 years, "Simpsons" creator Matt Groening has finally revealed the inspiration for the town where the show takes place.

In an interview with  Smithsonian magazine, Groening said the fictional Springfield that's home to "The Simpsons" was named after Springfield, Ore.

"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," Groening said. "When I grew up, I realized it was just a fictitious name. 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."

As for why he never said the show's Springfield was named after the small, Oregon town, Groening said, "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.'"

Springfield, Ore.'s community relations officer told ABC News Radio that while the city is happy for the attention, residents have known since 2007 that they were the real Springfield because of a plaque signed by Groening that says "Yo to Springfield, Oregon - the REAL Springfield!"