One of the longest-running jokes on The Simpsons is that the show always stops just shy of revealing which state its central town, Springfield, is set in. “I don’t want to ruin it for people, you know?” creator Matt Groening explains to Smithsonian magazine. “Whenever people say it’s Springfield, Ohio, or Springfield, Massachusetts, or Springfield, wherever, I always go, ‘Yup, that’s right.’” That said, Groening did have a specific location in mind: “Springfield was named after Springfield, Oregon. 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. 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.” Or, they did!