Fort Rouillé
The concrete walkways in this area delineate the walls of Fort Rouillé, a French trading post located on this site from 1750 to 1759. The reconstructed ground plan of Fort Rouillé is based on archaeological excavations conducted in 1979 and 1980 by the Toronto Historical Board, and on an excavation conducted in 1982 by the Youth Committee, Toronto Sesquicentennial Board. Over fifty young people, directed by professional archaeologists, participated in this excavation.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.