All of the states shaded are places I've visited. I counted the states that I drove through. I may not have visited the cities in-depth, but I think smelling their cows and seeing the landscapes constitute a good enough visit. I did not include the states that I've only seen their airport. (Though, I think that would have only added two more states: Arizona and Minnesota.) And actually, now that I think about it, I think I have driven through/visited Montana and maybe even South Dakota, but that was before I can remember.
All this shows me is that I have a lot more traveling to do even within the Country's borders.