The Thousand Islands are a chain of islands in the west end of the Saint Lawrence River in Ontario, Canada, where a branch of the Canadian Shield runs south across the river to join with the Adirondacks. The islands have long been popular with boaters. They extend approximately from Kingston, Ontario east to Brockville, Ontario.
Around twenty of these islands form the St. Lawrence Islands National Park, the smallest of Canada's national parks.
The Thousand Islands - Frontenac Arch region was designated a World Biosphere Reserve by UNESCO in 2002.
Not to be confused with the Rivière des Mille-Îles in southwestern Quebec.
