My first guess was that the legal climate was different between these states, but looking around on the web (http://www.beertown.org/homebrewing/legal.html for example) I don’t see any evidence for that idea – there are different laws from state to state but it sure doesn’t look like the law in ND is particularly restrictive. The second thing that comes to mind is that if you’re looking at states with population less than one million, it doesn’t take much to change from ’0-2 per million’ to ’20+’. An active homebrew club in Billings would be enough to change the stats. Measurement error also seems likely – I don’t see how these numbers were arrived at, but safe to guess they didn’t ask everyone everywhere whether they were craft brewers or not.
Well, that would make sense if you believe in the whole “folkways-surviving-in-the-New-World” hypothesis. The flatter, fertile parts of England are still the heartland of traditional small-scale ale brewing in the UK. The Scots-Irish prefer whisky/whiskey and Germans mainly drink lager of a style readily available in cans. African Americans had any Old World alcoholic patrimony knocked out of them under slavery.
Might I just inquire politely why the legend reads “0 > 2″ (and so on)?
Denver Mayor John Hickenlooper started as an oil geologist but when that industry tanked in the 1980s he started a very successful brew pub. He did so well he attracted lots of imitators. And then there’s Coors, so plenty of local pride tied into beer.