Did you think Prohibition was a thing from the past, associated with jazz and bootleggers and mobsters and Ken Burns documentaries and whatnot? That's cute, but as you can see from the map above produced by the BBC, there are still huge swaths of this country that are pretty strict about alcohol regulation. When Prohibition "ended," alcohol regulation was just put in the hands of states, many of which chose to continue the policies of Prohibition.
So where is it still hard/impossible to buy a drink? The Bible Belt, parts of Michigan and Pennsylvania, and a couple random counties in Nevada and South Dakota. Georgians, you're on your own.