the connection between Lake Superior and the rest of the Great Lakes

The Soo Locks, at Sault Ste. Marie, Michigan, bypass rapids on the St. Marys River that drop about 21 feet. Operated by the U.S. Army Corrps of Engineers, the locks handle an average of about 10,000 vessels a year, making them the busiest in the world. Vehicular traffic is carried over the locks by the Sault Ste. Marie International Bridge.

Prior to construction of the locks, boats had to be portaged around the rapids, meaning that cargo had to be unloaded onto wagons and then reloaded onto the boats down (or up) river. The first lock to bypass the rapids was built by the Northwest Fur Company in 1797. This 38-foot-long wooden lock was used until being destroyed during the War of 1812.

In 1852, the U.S. Congress granted 75,000 acres of land to the State of Michigan to be used as compensation to the company that built a new lock. The Fairbanks Scale Company undertook the project in 1853, and two 350-foot locks were completed and turned over to Michigan in 1855. The locks were transferred to the Army Corps of Engineers in 1881, and they have been operated toll free ever since (the original toll of four cents per ton was lowered to three cents in 1877).

The current system of locks is comprised of:
MacArthur Lock -- completed in 1943 -- 800 feet long, 80 feet wide, 29.5 feet deep (large enough to handle ocean-bound vessels that can pass through the Welland Canal, which bypasses Niagara Falls)
Poe Lock -- upgraded in 1968 -- 1,200 feet long, 110 feet wide, 32 feet deep (the only lock on the Great Lakes system capable of handing "Lakers," ships specially built to haul cargo within the Great Lakes
Davis Lock -- completed in 1914 -- 1,350 feet long, 80 feet wide, 23.1 feet deep
Sabin Lock -- completed in 1919 -- 1,350 feet long, 80 feet wide, 23.1 feet deep

The Soo Locks were designated as a National Historical Site and placed on the National Register of Historic Places on November 13, 1966.

SEE ALSO
Great Lakes
Sault Ste. Marie, Michigan
War of 1812
Niagara Falls

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This page was last updated on November 13, 2017.