<P> The Thousand Islands constitute an archipelago of 1,864 islands that straddles the Canada--US border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario . They stretch for about 50 miles (80 km) downstream from Kingston, Ontario . The Canadian islands are in the province of Ontario and the U.S. islands in the state of New York . </P> <P> The islands range in size from over 40 square miles (100 km) to smaller islands occupied by a single residence, or uninhabited outcroppings of rocks . To count as one of the Thousand Islands, emergent land within the river channel must have at least one square foot (0.093 m) of land above water level year - round, and support at least two living trees . </P> <P> The Thousand Islands archipelago is located at the outlet of Lake Ontario at the head of the Saint Lawrence River . The region is bisected by the Canada--United States border and covers portions of Jefferson and St. Lawrence counties in the U.S. state of New York, in addition to parts of the United Counties of Leeds and Grenville and Frontenac County in the Canadian province of Ontario . </P> <P> Geologically, the islands are located where a branch of the Canadian Shield runs south across the river to join with the Adirondacks . The Thousand Islands - Frontenac Arch region was designated a World Biosphere Reserve by UNESCO in 2002 . </P>

Where are the thousand islands located in canada
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