I am in New Orleans. There are white people, black people, a few asians and single percentage hispanics which are mostly cubans and hondurans. Very, very few mexicans. Probably less than 5% and they do not run businesses like restaurants. When I first lived here for a year in 97, they only had tortillas in the cold deli section of grocery stores, it was depressing. Really, they don't welcome brown people too easily down here.
There was a surge of taco trucks after katrina, they passed ordinances to run them off by requiring them to provide bathrooms (lame). I could probably still chase one down somewhere though. It is just really difficult to find anything close to authentic mexican food.
There is a place on Magazine called Juan's Flying Burritos, and they put white rice in their burritos, its gross. They call it creole hispanic food or something like that. They have crawfish enchiladas but their sauces are just not as good as what I am used to.
And there are also tex-mex-ish places here ran by white people but I can't stand black beans and that style of food. yuck.
The mexican population has been and is growing down here though. We actually found a little hole in the wall market around the corner recently that has lots of supplies too. I'm just used to all kinds of different mexican cuisines too.
Everything here is fried, it is terrible. And I won't even go into the lack of vegetarian cuisine here.