I have been asked, why do you use the name “a voice from the rustbelt”? Well, it places me culturally. I have seen other maps that include concentration of factories, coal, iron ore, and steel, or as Billy Joel sang about Allentown, “what was real, Iron and coke and chromium steel”. That was the result of Reaganomics and the resultant recession, which set up the pattern of the destruction of the working class, and the demonisation of the poor, and the ascendancy of the Republican Party in success and madness.
A few years ago the Harvard Dialect Survey was tabulated from over 30,000 speakers of English in the United States. One hundred twenty-two questions were used, and responses were charted to show the geographic distribution of answers. Sunday, the New York Times posted an interactive quiz [clicky] of twenty-five, and the collected responses were transformed into a temperature map [like one sees in a newspaper]. Blue is cold, red is hot; blue is unlike your usage, red mirrors your usage. It spotlights the most similar cities indicative of your speech, and the three most dissimilar. I tried the test several times, and the questions came from a pool. A few answers are elicited from a very small geographic area*. Other more general responses† shade and blend the color assignments. Depending on the questions asked, and which [sometimes more than one choice applies] of the multiple choices one selects, the shading would shift; but not very greatly.
I had a shift that included Pittsburgh, Philadelphia, and Baltimore. I had a shift that included New Orleans, and Baton Rouge [one answer in a small group of questions can throw the results elsewhere]. I had a shift that included Detroit and Toledo. The most common shift i had was Rockford, Grand Rapids, and Cleveland. I had a Cleveland, Akron, and Pittsburgh too. The Pacific West, the Great Basin, and New England were always cold. A couple of answers would yellow up the south, outside of Florida.
*There are phrases that have a small and localised distribution; and they peg you. e.g., October 30th is _____. The problem with that, is one may have knowledge without currency.
†Looking at other sources too, a big national division occurs with the vowel vocalised in the pair of words cot/caught, and pin/pen. i use different vowels.