Springfield is the capital and seat of government of Illinois though Chicago is also in Illinois and much bigger. Illinois is thick in the Bible Belt but religion tends to be imposed more in rural areas than in large towns and cities.
The tomb of Abraham Lincoln is in Springfield as are other Lincoln memorials.  Abraham Lincoln lived in Springfield for seventeen years.
Springfield is also the name of a town in neighboring Missouri. There are also many states in America possessing a city named "Springfield".
Springfield is also the main city in The Simpsons of an unknown state, although it has been highly-speculated to be Oregon, where the show's creator grew up .