This report from the Substance Abuse and Mental Health Services Administration (SAMHSA) details drug use across the 50 states based on the 2006 and 2007 National Surveys on Drug Use and Health, which involved interviews with over 135,000 people around the country. It revealed a rather wide range of reported drug use between states, as you can see in this map, which is derived from a map in the report:
The report actually has its own maps, but I warn you that they are very ugly. That's why I had to make my own.
A couple things are striking about this map. The less surprising of these things is that there's a very wide range in the numbers of people who report using drugs in the past year - from 5.55% in North Dakota to 11.10% in Alaska. I should say: in itself this isn't surprising, but the particular pattern of the distribution does surprise me somewhat. I would expect higher rates of drug use in states with smaller rural populations, but this map seems to show that that's just a false intuition.
The other striking thing about the map - and another thing that challenges my prejudices - is that there doesn't seem to be any correlation between the wealth or human development of states and their level of drug use. Some high-development states, like New Jersey and Pennsylvania, have low levels of drug use; and some, like Massachusetts and Colorado, have high levels of drug use. And some low-development states, like Arkansas and Tennessee, have high levels of drug use, while others, like South Carolina and Alabama, have low levels of drug use. There do seem to be some regional trends - especially the high rates of drug use in the non-Mormon West - but a lot of variation within regions as well. All in all it just looks pretty random. What do you think - am I missing something here?
(Thanks to Nikolas Schiller for the link.)
UPDATE: Richard Florida has some interesting follow-up in a couple of posts; he uses actual statistics and stuff do dig into this data a bit more. (One tidbit: more people do drugs in Obama states! Republicans ought to appreciate that. Come to think of it, Democrats might appreciate that as well...)