Earlier this year Fortune pulled this awesome map from their archives, showing the where and how of booze distribution during Prohibition, in 1931 specifically:

Map showing distribution of booze during Prohibition

The liquor business is big business and follows essentially the distribution methods of any big business. It boasts a normal alignment of national operators, middlemen, and retailers; uses railroads, fleets of trucks, steamers, barges, airplanes, et al. The secrecy with which its operations are carried on is not such as would seem out of place in, say, the chemical industry, where armed guards patrol locked factory gates; or in the factory of any canny manufacturer who sets his dials to read in error and so deceive competitors’ spies as to the temperature of his annealing.

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Click here to see a higher resolution version of the map (opens in a new tab).

Go check out the entire article at Forbes.