...some of you have listed places in other parts of the country, like MN and WV and other places where it's hard to conceive that any place there could provide authentic Mexican Food...
why? Mexicans are all over this country. Maybe not as plentiful as your state of AZ, but Mexican cuisine can be found in many places.
In WV, housing is more affordable, and now Eastern WV has become part of the DC Metro/Northern VA metro area, new construction abounds in WV. Bringing in jobs that have a high % of Mexican workers, from building construction to electrical, to landscaping, to roadwork and, the new Mexican restaurants, just to name a few jobs.
I'd be willing to bet, that the same is true in and around other major metropolitan areas, like Minneapolis, or Piedmont Triad area of NC, and so on and so on.
The population of Mexicans, now Americans, has skyrocketed, and as the Mexican people assimilate into the US, they, like the droves of immigrants before them, such as my ancestors, are moving all over the country.