Thousand Islands International Bridge

Groundbreaking took place on 30 April 1937, and the system was finished in about sixteen months, roughly ten weeks ahead of schedule. Wikipedia gives the cost as $3.05 million. Franklin D. Roosevelt and Canadian Prime Minister William Lyon Mackenzie King dedicated it before a crowd reported at over 25,000. Roosevelt spoke from a lectern beneath the mainland approach to the American span, and the two leaders were then the first dignitaries to drive across. At the ceremony Roosevelt called the bridge an open door, and King described it as a symbol of friendship and goodwill between the two countries.

The American span replaced the Lewis Ferry route to Wellesley Island and was built almost on top of it. In its first year, more than 118,000 vehicles crossed, and annual crossings exceeded 2 million by 2019.

Federal Bridge Corporation records give a month-by-month timeline. Foundation work began on both the American and Canadian sides in May 1937. Steel erection started in Canada in September and in the United States in October 1937, and the foundations were complete by December. Cable work ran from March to April 1938, deck paving began in May 1938, and the steel was finished on the American span in June and on the Canadian spans in August 1938, when paving was also completed.

A local history published for the bridge's 80th anniversary lists the scale of the work: about 575,000 man-hours of labour, 20,700 cubic yards of concrete, 6,550 tons of structural and other steel, 798 tons of reinforcing steel and 555 tons of cable material. Wikipedia adds that aerodynamic oscillation problems appeared soon after opening and were corrected through structural upgrades.

From south to north, the five bridges are: the U.S. mainland to Wellesley Island, Wellesley Island to Hill Island, Hill Island to Constance Island, Constance Island to Georgina Island and Georgina Island to the Canadian mainland. Sources count them differently, with some describing seven spans, which is consistent once spans and bridges are counted separately. The designs combine suspension, arch and truss types. The longest spans are about 800 ft for the American suspension span, 750 ft for the Canadian suspension span and 600 ft for the Canadian truss, with clearances of 150 ft on the U.S. side and 120 ft on the Canadian side.

The American crossing, from the mainland to Wellesley Island, measures about 4,500 ft abutment to abutment, and the Canadian crossing about 3,330 ft. On the Canadian side, a 600-ft continuous Warren truss runs from Hill Island to Constance Island, a 348-ft steel arch from Constance Island to Georgina Island, and a 750-ft suspension span on to the mainland. The bridges carry one lane in each direction plus a narrow pedestrian walkway, which one local account puts at about three feet wide and separated from traffic by a steel railing.

The actual international crossing, between Wellesley and Hill Islands, is a short bridge of about 90 ft over a small channel. A parallel span was added in 1959 to relieve congestion at the ports of entry; Wikipedia describes the border crossing today as two parallel 90-ft bridges.

The Thousand Islands Bridge Authority, a New York public benefit corporation created in 1933, operates the system, with Canada's Federal Bridge Corporation as partner under a joint agreement. Per Wikipedia, the Authority has a seven-member board of four Americans and three Canadians, appointed by the Jefferson County Board of Legislators. It also maintains Boldt Castle. On the U.S. side the bridge connects with I-81, and on the Canadian side Highway 137 leads to Highway 401, with an interchange for the Thousand Islands Parkway.

Maintenance is near-constant. The Authority's history notes that the bridge is washed once a year, that painting normally runs from June through October, and that painting a single span takes about seven years. It also cites roughly $28 million in U.S. and Canadian deck replacement projects in the decades after opening, paid for from bridge tolls.

The bridge is a working border crossing for vehicles and pedestrians, so carry valid passports. Check the Bridge Authority and border agencies for current tolls, wait times and requirements, since summer waits can be long. The long arches are worth watching for views over the islands, but verify with the operator whether stopping is permitted anywhere.

On a Voyzo private tour with a private vehicle and driver, you stay in the same seat through the border formalities and over the spans, which makes the Thousand Islands scenery easy to enjoy.

The crossing sits within reach of Gananoque, Ivy Lea, Wellesley Island and Alexandria Bay. Wikipedia notes it is the westernmost of the three St. Lawrence River road crossings, with Lake Ontario upstream and the Ogdensburg-Prescott International Bridge downstream.