The Thirty Thousand Islands are the world's largest freshwater archipelago, and are located mainly along the east side of Georgian Bay, part of the Great Lakes, in Ontario, Canada.
It is an area of 347,000 hectares (860,000 acres) that stretches 200 kilometres (120 mi) along the eastern coast from Port Severn to the French River.
Many of the Group of Seven landscape paintings feature the Georgian Bay Shoreline and the adjacent windswept islands with their distinctive trees and large boulders, which are characteristic features of the Canadian Shield.
Casson and Tom Thomson all painted extensively along Georgian Bay.
At that time, they came by train as the road to Killarney, Ontario would not be built until four decades later.