I number myself in that odd group. I tell people that I have lived in 26 states and 3 countries. That is to say, I was alive while I was in them. I wasn't dead. That means I lived in every one of those states, albeit mostly for short periods.
Now, with the advent of making travels for Project Trails as a part of the Gilder Lehrman Institute, I stand to add at least four states to my list during the next five years - New Jersey (I never thought I'd go to New Jersey.), Massachusetts, Pennsylvania, and Montana. That will round out my state visits to 30 out of 50: three-fifths of the United States have felt the imprint of my shoe. If things don't work out for my continual part in the program, the number will not rise, and if we get to add some travel to those trips, perhaps the number could be even higher.
On average, the American visits 12 1/2 states in his lifetime. I have been in four of the five most-visited states, which are Florida, California, Georgia, New York, and Nevada (I haven't been to Nevada, and it's not high on my list.). The least-visited are Montana, Nebraska (It's not for everyone.), Rhode Island, South Dakota (beautiful), Vermont (likewise, beautiful), Idaho, Alaska, and North Dakota, of which I've been to three of the eight. I've already doubled the average, and will be halfway to tripling it (Of course, the average could shift as well.)
For what it's worth, I will also add Washington, DC - the first time I will be in the United States without being in a united state. When I flew to Ronald Reagan International a few years ago, I was still across the Potomac from DC, in Virginia for the first time, headed for George Washington's Mount Vernon. I have seen DC, but not stepped into it.
There are Hawaii and Alaska, of course. We can add to that Washington and Oregon, and in no particular order, Idaho, North Dakota, Wyoming, Utah, and Nevada. Minnesota, Wisconsin, Michigan, and Ohio could be listed next, alongside West Virginia, and South Carolina (I've been to all of SC's neighboring states though.). That leaves Delaware, Connecticut, and Rhode Island, along with New Hampshire and Maine. That list doesn't include the states I will visit with Gilder Lehrman in the next five years, so until then, I still have to add New Jersey, Massachusetts, Pennsylvania, and Montana.