On October 31, 1962, the Sault Ste. Marie International Bridge officially opened to traffic, establishing a permanent highway connection between the United States and Canada across the St. Marys River.

The landmark infrastructure project connected Sault Ste. Marie in the American state of Michigan with the city of the same name in Ontario, Canada, marking an important development in North American transportation and engineering history. The international crossing extends approximately 2.8 miles, equivalent to 4.5 kilometres, and provides a vital road connection between the two neighbouring communities. Construction began in September 1960 and was completed in 1962, with the bridge officially opening on October 31 of that year. Before the crossing was established, travellers between the two cities relied primarily on ferry services. A railway bridge also existed across the river, but a permanent highway crossing was needed to facilitate road transportation.

The project incorporated steel truss arch structures designed to accommodate the complex geography and water transportation facilities along the St. Marys River. On the American side, the bridge features a double-arch steel structure spanning the Soo Locks, while a single-arch structure crosses the Canadian navigation facilities. The river is an important part of the Great Lakes transportation system, connecting Lake Superior with Lake Huron and supporting commercial shipping through an extensive network of navigation locks. Developing a permanent road connection across this active waterway represented an important engineering achievement, requiring structures capable of carrying road traffic while maintaining clearance for existing navigation facilities.

The completed bridge improved cross-border access for residents, businesses and commercial transportation operators, strengthening regional connections between Michigan and Ontario.The crossing is managed through cooperation between American and Canadian authorities, including the Michigan Department of Transportation and the relevant Canadian federal bridge agencies. According to the Sault Ste. Marie International Bridge administration, more than 107 million vehicle crossings have been recorded since the bridge opened in 1962. To commemorate its 64th anniversary on October 31, 2026, bridge authorities announced a special 24-hour reduction in passenger vehicle tolls. Under the anniversary arrangement, the toll was reduced to US$1.50 for American payments and C$2 for Canadian payments, reflecting historical rates from the bridge's early years. The initiative was introduced to recognise the longstanding relationship between the two communities and the bridge's continuing role in cross-border mobility.

Sixty-four years after its opening, the Sault Ste. Marie International Bridge remains an important example of international infrastructure cooperation.

Its construction illustrates how major transportation projects can overcome geographical barriers, improve access between neighbouring communities and create lasting connections supporting trade and regional development.