Incredible Soo Locks | 14 Things You Didn't Know About the Soo Locks - An Engineering Marvel! | See How the Locks Work! 

Incredible Soo Locks | 14 Things You Didn't Know About the Soo Locks |  By: Sherry Trautman | | Updated: October 25, 2022

Thanks to the innovative Soo Locks in Sault Ste Marie Michigan, freighters over 1,000 feet in length can traverse freely along the St. Marys River all the way from Duluth, Minnesota outward into the Atlantic Ocean and beyond!

How Do The Soo Locks Work? See a Demonstration and Come Along As We Pass Through the Locks!

Did You Know There Are Two Locks?

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  1. The Poe Lock is used by larger ships as it is 1,200 feet.  This lock was rebuilt in 1968. 
  2. The MacArthur Lock is 800 feet and was built in 1943. You can see this lock easily as it is the closet to the observation deck in the Soo Locks Park.

Soo Locks FAQ and Fun Facts!

  1. Why is it called the Soo Locks? Who is the Poe Lock named after? In 1896, after 10 years of construction, the Poe Lock opened and was named after General Orlando M. Poe. General Poe oversaw Great Lakes improvements and recommended the new lock at the Soo. The MacArthur Lock was named after General Douglas MacArthur.
  2. When were the locks constructed? The original Poe Lock was coompleted in 1896 and rebuilt in 1968 to accommodate larger and more modern ships. The MacArthur Lock was constructed in 1943.
  3. What two bodies of water does the Soo Locks connect?  Lake Huron and Lake Superior
  4. Is the water pumped in or out? The Soo Locks does not utilize pumps! They are 100% gravity fed!  See the water fill in our video above!
  5. How long is the Poe Lock?  Poe Lock is 1,200 feet long and 110 feet wide.
  6. How many gallons of water are in the Soo Lock? The Poe Lock uses 22 million gallons of water to lift or lower vessels. 
  7. How does the Soo Locks Work? The locks are powered by gravity!  Water rushes in and out of the lock chambers by opening and closing valves. The boat enters the lock with the filling value open.  The locks are closed and then the emptying value opens, dropping the water level 21 feet inside the locks.  The doors open and the vessel can continue thorugh the locks. The locks allow boats to traverse a 21-foot drop. See our video above to learn more!
  8. How much does it cost to go through the Soo Locks?  Free!  After the US government took over, an agreement was made that the locks would be free to pass through. 
  9. How many people visit the Soo Locks each year? It’s estimated that 500,000 people visit these iconic locks!
  10. How many vessels/ships pass through the Soo Locks each year?  Approximately 7,000! They carry about 86 million tons of cargo!!
  11. Does iron ore pass through the locks? YES! In fact, approximately 90% of the United State’s Iron Ore passes through the Soo Locks!
  12. When are the Soo Locks Open? They are open 24 hours a day!
  13. How often do ships go through the Soo Locks? The locks pass an average of 10,000 ships per year!
  14. Do the Locks ever close?  The Soo Locks are closed during the winter from January through March, when ice shuts down shipping on the Great Lakes.

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It takes freighters about 9 hours to pass through the 63 mile long St. Marys River between Lake Superior and Lake Huron!

Breaking Records at the Soo Locks!

Around the time the newly reconstructed Poe Lock was completed (fall of 1968), the 730-foot Edmund Fitzgerald locked downbound through the MacArthur Lock carrying 30,200 tons of taconite pellets. The massive load on the Edmund Fitzgerald broke an all-time tonnage record for a single ship through the locks!  

Not to be outdone, but....

Four years later, the first 1,000-footer, the Stewart J. Cort, locked through the Poe Locks carrying 51,000 tons of taconite, thus setting a new record! 

In recent years, boats carrying loads in excess of 70,000 tons have passed through the locks!

Two Best Ways To See the Soo Locks

  1. It's absolutely fascinating to watch the large freighters entering the locks from the observation platform located in the Soo Locks.  The observation platform overlooks the MacArthur Lock.
  2. Take a Soo Locks Boat Tour!  

Estimated Sailing Times and Distances From the Soo Locks

Who Can Use the Soo Locks?

From the observation platform, you can see a wide range of vessels including imassive Great Lakes freighters, tall ships, sailboats, cruise ships, tour boats, personal boats, and military crafts lock into Lake Superior or Lake Huron. By the way, you will pass through it too if you take a Soo Locks boat tour!

Pin This Super Fun Soo Locks Page!

YouTube Video!

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About the Lead Author | Sherry Trautman

Thanks for stopping by!

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    Sherry Trautman is a seasoned business owner and a multifaceted content creator, deeply entrenched in the world of travel in Michigan. With her extensive background in writing, editing, photography, marketing, website design, web mastering, social media, and publishing, she is the driving force behind the acclaimed Michigan Travel site "" A lifelong Michigander, Sherry's journey began in Mt. Pleasant, Michigan led her to St. Joseph during her formative years, and further to Kalamazoo for her higher education. She holds a Bachelor of Science in Industrial Design and Fine Art from Western Michigan University. Her career initially blossomed in Battle Creek, where she contributed significantly to aviation, marketing, and the art industry.

    In 2018, Sherry, alongside her husband Chris, embarked on a passionate endeavor with the inception of This venture was not just a business but a full-time commitment to exploring and celebrating the diverse landscapes and communities of Michigan. Together, they tirelessly traverse the state, curating unique experiences, capturing stunning visuals, and weaving engaging narratives that showcase Michigan's rich cultural tapestry and natural beauty. From her early experiences in different Michigander locales to her extensive professional background, Sherry's life and work epitomize a deep-rooted expertise in Michigan travel, making her an authoritative voice in this niche.

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