Thousand Islands Bridge, New York

The Thousand Islands Bridge is the international border crossing for Interstate 81, and is the westernmost of the three bridges that cross the boundary over the St. Lawrence River. This is a major crossing, with up to two hour delays in the summer. The boundary snakes through small channels around the islands in the diffused river, until it runs between Wellesley Island and Hill Island, and underneath the Thousand Islands Bridge. 30 miles west, the river and the boundary spill into Lake Ontario, south of Kingston, Ontario.