St. Marys River (Michigan–Ontario) St. Marys River (Michigan–Ontario) The St. Marys River (), sometimes written as the St. Mary's River, drains Lake Superior, starting at the end of Whitefish Bay and flowing southeast into Lake Huron, with a fall of . For its entire length it is an international border, separating Michigan in the United States from Ontario, Canada. The twin cities of Sault Ste. Marie, Ontario, and Sault Ste. Marie, Michigan are connected across the St. Marys River by the Sault Ste. Marie International Bridge. The St. Marys Rapids are just below the river's exit from Lake Superior and can be bypassed by
Sault Ste. Marie International Bridge MP Carmen Provenzano, was officially opened in September 2006. Construction work subsequently commenced in 2009 on a project to expand and modernize the Canadian bridge plaza, including a larger Canada Border Services Agency building with improved truck inspection facilities and a dedicated route to take trucks directly to Carmen's Way, thereby eliminating the need for trucking traffic to enter Huron Street. Beginning in May 2014, construction work commenced on improvements to the plaza on the Michigan side of the bridge. The 100 millionth crossing occurred on March 1, 2018. Sault Ste. Marie International Bridge The Sault Ste. Marie International Bridge