Piccadilly is a small town in the Adelaide Hills of South Australia, Australia. At the 2006 census, Piccadilly had a population of 509. The Piccadill…Piccadilly is a small town in the Adelaide Hills of South Australia, Australia. At the 2006 census, Piccadilly had a population of 509. The Piccadilly Valley was for many decades a market gardening centre which produced food for the Adelaide and overseas market. A large part of the valley is now used for growing premium 'cool climate' grape varieties.