Working Together in Lock Step

The Soo Locks, which date back to the 1800s, are the major cargo connection point between Lakes Superior and Huron. The locks allow the movement of approximately 86 million tons of freight annually through the Great Lakes, the St. Lawrence Seaway and the international markets. Considered a feat of engineering, the locks raise and lower boats to allow passage between the two Great Lakes using a series of gates and chambers that are powered solely by gravity, without the use of any pumps. The Soo Locks are currently made up of the Poe, MacArthur, Davis and Sabin locks. The Poe Lock, the most utilized of the four, was rebuilt in the 1960s to accommodate larger ships. Currently, approximately 90% of the commodities transported through the Soo Locks are restricted to the size of the Poe Lock. The MacArthur Lock, the southernmost lock, is also currently operational. Neither the Davis nor the Sabin Lock are currently in operation.