Knight Frank recently voted chicago as the sixth best city in the world for the uber rich to live, work, and play. Coincidentally, Illinois also ranks number six of U.S. states by number of billionaire residents. It's without a doubt that this corner of america is home to some seriously swanky citizens, but where do they live? Believe it or not, the 25 wealthiest places in Illinois are all suburbs and that is exactly where you'll find many of Chicago's richest residents.