As others have said, downstate means "south" Illinois. I'd add that it also means rural, instead of urban (Chicago, in up-state). The term "downstate" can't be

As others have said, downstate means "south" Illinois. I'd add that it also means rural, instead of urban (Chicago, in up-state). The term "downstate" can't be universally applied to mean rural though; if we were discussing the same situation in New York, we'd talk about "upstate Donny".