The Illinois state fair is pretty good, they have an awesome butter cow. It's located in Springfield which, while not entirely urban, is fairly citified. But there is plenty of country around there and interesting sights like Route 66.

I have always wanted to see the corn palace in South Dakota but I'm not sure if it is attached to the state fair there.

Most state fairs have pretty impressive music lineups. You might research the music acts and see if any appeal to you and use that to help decide.