(1) With time, dedication, and guidance, you can gain a really excellent foundation in history basically anywhere through reading! It would help if you had access to a top-notch college library, even if you can only read books there. So - anywhere.

(2) If you are interested in local history, particularly on the town/county level, then you'd want to live in the place you're interested in or be interested in the place where you live.

(3) For graduate school, the answer depends entirely on what you want to study within history. The best school for medieval Europe will not be the best school for modern Africa. And even within "medieval Europe," the best place to study early medieval economics is not the best place to study medieval religious women. And so forth.

That applies to PhD programs that grant full funding. The best place to get a master's is, within reasonable limits of a school's decent-ness, the place that gives you the best financial deal.

Did you have any particular field of history that you wanted to study? Because different schools are better for different fields of history. I'll give you the same advice my mentor told me. Go through your all the history books you've read about on your favorite subject. Look up the names of the authors and take a look at the university at which they teach.