Indiana, Illinois, Missouri, Kentucky, Tennessee, Georgia, Alabama, Mississippi, Arkansas, Louisiana, Texas, Florida, South Caroline, North Carolina, Virginia, Maryland, Delaware, Pennsylvania, Ohio, New York, Connecticut, Arizona, Michigan, Wisconsin, Iowa, Washington D.C., and Colorado in the United States.
Been to Toronto, Canada. Rounds out North America
Been to United Kingdom (England and Scotland), France, Belgium, Netherlands, Germany, Luxembourg, Austria, Denmark, and Sweden in Europe.
whatever states happen to be between California and Michigan not already listed (I was too young to actually remember what states we passed through)
later this month Kansas and Washington state
Layovers (probably don't really count, but whatever):