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David Silverman, a director for the Simpsons, has claimed that Springfield is in the fictional state of "North Tacoma" (or "North Takoma"). This is substantiated by the state abbreviations NT and TA used within the show. However, this has never been officially confirmed in any canonical episode of The Simpsons or by other Simpsons producers. And on Homer's Driver License the state is NT and the zip code is 49007, which is a Kalamazoo, Michigan zip code