Soo Locks, Sault Saint Marie, Michigan, USA
Read more about How the Soo Locks Were Made at Lake Superior Magazine.
Learn more about How the Soo Locks Work at the US Army Corps of Engineers Soo Locks website.
Watch the Paul R. Tregurtha--the largest ship on the Great Lakes--pass through the Soo Locks in this time-lapse video:
Lake Superior is the largest of the Great Lakes, and the second largest fresh water lake in the world. Its basin holds over 2,900 cubic miles of fresh water, which is replenished by over 200 rivers in its drainage basin. All of this water pouring into Lake Superior makes its way out again through a single outlet: The St. Mary's River.
Originally, water from Lake Superior had to flow through the St. Mary's rapids, dropping a total of 21 feet before it reached the elevation of Lake Huron. Before the Soo Locks were built, cargo had to be unloaded from ships and portaged overland around the rapids, slowing transit and requiring expensive labor.
The difficulty was so great that the British Northwest Company created the first lock on the north side of St Mary's River in 1797, large enough to allow 30-foot canoes loaded with furs and trade goods to pass through safely and without the long portage. U.S. forces destroyed this first lock during the War of 1812, but both U.S. and Canadian governments built additional locks during the centuries that followed to accommodate growing traffic on the Great Lakes.
Quick Facts about the Soo Locks:
The first lock connecting Lake Superior to Lake Huron was built by the British North West Company on the St. Mary's River in 1797. At the time, the North West Company controlled nearly 80% of the Great Lakes fur trade, rivaling the Hudson Bay Company. This lock, built on the north shore of the river, was 38 feet long to accommodate 30-foot canoes transporting goods between the company's headquarters in Montreal and buyers in the northwest territories. The lock bypassed the rapids and lifted canoes 9 feet, easing their passage from lake to lake. This original lock was destroyed by American forces in the War of 1812, but the young United States soon found it essential to build a lock of its own.
The first lock on the US side of the river was built in 1855, called State Lock.