LOL at how often this has been searched on Google... Moe said in a recent episode of The Simpsons that he only moved to Springfield because the Zip code spells "BOOBS" on a calculator, so that is 80085... Unfortunately 80085 doesn't cover some town called Springfield, in fact it doesn't cover anywhere- it is as of yet unassigned, though if it one day came into existence it would probably be assigned to part of Colorado. So could Springfield be really based in Colorado? We know it has mountains and a gorge so possibly, but the mythical Springfield also has been shown to have a sea shore, even close enough to an off-shore oil rig accessible by raft- so Colorado probably is not the home of the 'real' Springfield. Interestingly zip cod 58008 was also highly searched for because you often turn a calculator upside down when reading words... this zip code does exist, and ironically is Barney, North Dakota, not Springfield but the name of Homer's best friend- coincidence or did the writers know this? There is a Springfield, ND but it is a small farming town 4 and a half hours North of Barney, in the middle of nowhere extreme North- not the climate of the Springfield we know and love.