Due to the strategic location of the river and the abundant natural resources found here, the French and British often fought over the area and the right to trade with Native Americans in the 1700’s.
In 1820, the Treaty of the Sault was signed, which turned control over to the United States in 1823. Fort Brady was built on the grounds of the old French Fort Repentigny, as the new Americans were concerned about possible British invasions from nearby Canada. This fort was eventually abandoned in the 1890’s, and a new Fort Brady was constructed on the grounds of present-day Lake Superior State University. Throughout all this turbulent history, the St. Mary’s River continued to dominate the life and events of Sault Ste. Marie—as it continues to do so today.
The world-famous Soo Locks, which overcome the natural barriers to navigation, continue to be an engineering marvel, and a source of great pride for residents. The first lock was constructed in the late 1700’s on the Canadian side of the river by the Northwest Fur Company, but was destroyed during the War of 1812. Other primitive lock systems followed until 1850, when the present-day lock system began to be developed by civil engineers.