The Thousand Islands are a chain of islands that straddle the U.S-Canada border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. The islands stretch for about 50 mi (80 km) downstream from Kingston, Ontario Canadian islands are in the province of Ontario. The U.S. islands are in the state of New York. The islands, which number 1,865 in all, range in size from over 100 km² (40 sq mi) to smaller islands occupied by a single residence, to even smaller uninhabited outcroppings of rocks that are home to migratory waterfowl. The number of islands was determined using the criteria that any island must be above water level for 365 days per year, bigger than one square foot (roughly 900 cm²), and support at least one tree or shrub. The area is very popular among vacationers, campers, and boaters, and is often referred to as the 'fresh water boating capital of the world.' The number of islands was determined using the criteria that any island must be above water level for 365 days per year, bigger than one square foot (roughly 900 cm²), and support at least one tree or shrub. The area is very popular among vacationers, campers, and boaters, and is often referred to as the 'fresh water boating capital of the world.'