Main Duck Island, twelve miles from the shore of Prince Edward, was a convenient staging point for rumrunners smuggling liquor into the United States during Prohibition. In the early years, possession of alcoholic beverages for personal use was still legal in Ontario, and although the island was occasionally raided, there was little federal agents could do to prevent stockpiling of whiskey, which was subsequently taken to the American shore at a convenient time.
However, a bizarre situation developed when the Ontario Government bowed to pressure from Temperance organizers and prohibited the sale and consumption of alcohol in the province. Manufacture of liquor for export purposes was still legal. Boatload after boatload of export whiskey left the Ontario distilleries, only to be smuggled back into the province and boot-legged to local consumers. This was far safer than slipping past American law enforcement officers, and fortunes were made in the County from the rum-running business. Many small operators sold a few cases of whiskey here and there to eke out the family income, and an unbelievable number of local residents were involved on an occasional basis. Unfortunately for the smugglers, Ontario eventually cracked down on rumrunning, and one by one the amateurs dropped out, leaving the hazardous profession in the hands of a daring few.
Source: Kellough, Janet. The Legendary Guide to Prince Edward County. Picton, Ont.: Kellough Productions, 1994.