The phrase "Best Location in the Nation," seems to have been coined in the 1940s. Still very popular in the 1960s and 1970s, it comes from the fact that Cleveland is 600 miles from 60% of the U.S. (and a good chunk of Canada).
This shirt reminds me of something that was said while growing up in Cleveland, Ohio. I wear it proudly because no matter the detractors who never visited my hometown, I can tell you Cleveland is what we said it is.