Innisfil is a town in Ontario, Canada, located on the western shore of Lake Simcoe in Simcoe County, immediately south of Barrie and 80 kilome…Innisfil is a town in Ontario, Canada, located on the western shore of Lake Simcoe in Simcoe County, immediately south of Barrie and 80 kilometres north of Toronto. It has historically been a rural area, but since it is geographically sandwiched between the high-growth areas of Barrie and the York Region, there has been growing residential development in Innisfil.