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, Ontario Sault Ste. Marie Canal, which was completed in 1895. Sault Ste. Marie, Ontario was incorporated as a town in 1887 and a city in 1912. The town gained brief international notoriety in 1911 in the trial of Angelina Napolitano, the first person in Canada to use the battered woman defence for murder. During World War II, and particularly after the US was attacked at Pearl Harbor in 1941, government concern turned to protection of the locks and shipping channel at Sault Ste. Marie. A substantial military presence was established to protect the locks from a possible attack by Nazi German