Thousand Islands is a group of more than a thousand islands in the St. Lawrence River. The group includes islands on both sides of the boundary between Canada and the United States. No complete count has ever been made, because some of the islands are only small points of rock above the water. But at least 1,700 islands compose the group. A few of the islands are as much as 5 to 6 miles (8 to 10 kilometers) in length. The islands lie in a 40-mile (64-kilometer) stretch of the St. Lawrence where the river runs from 4 to 7 miles (6 to 11 kilometers) wide as it leaves Lake Ontario. They are formed where the river flows over the low hills of the Canadian Shield, which extends southeast into New York state (see Canadian Shield ).
These rocky islands are noted for their beautiful scenery and mild summer climate. Many have popular public summer resorts. Several have luxurious summer homes. Some of the islands are part of Thousand Islands National Park. The park has been made into a recreational center and game preserve.
The Thousand Islands International Bridge, completed in 1938, spans some of the islands. It consists of two main suspension structures, three smaller bridges, and roadways across two islands. Its total length is about 61/2 miles (10.5 kilometers).
