The usual suspects for the big festival tourneys over the years would be the Firemens, Mcquades, etc....
But that is not what I am talking about. I am pointing out each region has their own established D & C program that they run throughout the year. If you are not keeping up then I'll help you.
Some obvious mainstays have been: Minnesota, Iowa and other mid west states, Southern Calif, Dakotas, New Jersey, Pacific NW, etc....
Feel free to do your own research over the last 20 years and see what type of representation states have at nationals.