Sault Ste. Marie International Railroad Bridge, Railway bridge at St. Marys River, United States and Canada

The Sault Ste. Marie International Railroad Bridge carries the CN Manistique Subdivision over the St. Marys River between Michigan and Ontario, running parallel to the Sault Ste. Marie International Bridge. From south to north it consists of a plate girder overpass above West Pier Drive, a lift bridge, a bascule bridge, a nine-span thru-truss, a swing bridge and a second plate girder span.

The bridge was first built in 1887 to carry rail traffic across the St. Marys River and the international border between Sault Ste. Marie, Michigan, and Sault Ste. Marie, Ontario. Its earliest section is the nine-span thru-truss, completed that year. As the Soo Locks were enlarged for larger ships, some thru-truss spans were removed and replaced by lift, bascule and swing bridges.

The bridge represents the longstanding transportation partnership between Michigan and Ontario through its continuous operation as a railway connection point.

The bridge carries the CN Manistique Subdivision over the St. Marys River, crossing the Soo Locks canals, the falls and the Sault Ste. Marie Canal in Ontario. It runs parallel to the Sault Ste. Marie International Bridge, so the two crossings can be seen side by side from the riverbanks.

The bridge's oldest section is a nine-span through-truss completed in 1887. As the Soo Locks were enlarged for larger ships, some of those truss spans were removed and replaced by lift, bascule and swing bridges, so the crossing now mixes eras as well as designs.