Often cited as one of the most integral parts of the United States’ entire economic infrastructure, the modern-day Poe Lock is celebrating 50 years of providing the means for massive freighters to traverse into and out of Lake Superior.

The current Poe Lock measures 1,200 feet long, 110 feet wide and 32 feet deep. When a 1,000-foot freighter passes through the St. Marys River it has to be locked through the Poe. It serves as the newest and most frequently used member of the Soo Locks along with the MacArthur and the dormant Sabin and Davis Locks.

Philip R. Clarke

Wednesday, June, 26 2019 marks 50 years since the Poe Lock had an inauguration ceremony to mark its opening. The Philip R. Clarke, the first freighter to pass through the modern Poe Lock, made another passthrough last week, almost half a century to the day of its original locking.

“The Poe is the largest lock we have on-site and the only one that can handle boats longer than 730 feet long,” said United States Army Corps of Engineers Park Ranger Michelle Briggs. “There are only a handful of American cargo vessels on the Great Lakes that are small enough to fit in the MacArthur Lock, so the steady shipment of raw materials to ports on the lower lakes depends on the Poe Lock.”

According to a recent United States Army Corps of Engineers economic vitality study, the Poe Lock handles 89 percent of the tonnage that passed through the Soo Locks and on average has 60 million tons of cargo (mostly taconite) that passes through it annually.

Originally built as the third Soo Lock in 1896 to replace the State Lock, the Poe, engineered by Orlando Poe, was once the largest lock in the word measuring 800 feet long and 100 feet wide. As ships began to exponentially grow throughout the first half of the 20th century, and with the Saint Lawrence Seaway opening allowing passage into the Great Lakes, the need for an even larger lock grew.

Philip R. Clarke 1969

The Philip R. Clarke passes through the Poe Lock in 1969, during the ceremony commemorating the its opening. (Photo Courtesy of the USACE)

Planning began in 1958 to replace the first Poe Lock with a larger and deeper chamber. Once construction on the rebuild wrapped in 1968 it was officially christened with a ceremony on June 26, 1969. The then-647 feet long (now 767) Phillip R. Clarke was the first vessel to be locked through the Poe on that June day. Four years later, the first 1,000-foot-long freighters passed through it.

“Visitors are always impressed with the size of the 1,000 footers as they glide into the Poe Lock. They are even more amazed to learn how tightly they fit in that lock. The freighters are 105 feet wide and the lock is 110,” explained Briggs.

With Soo Locks Engineers Day right around the corner on Friday, upwards of 10,000 visitors will have a chance to checkout the mighty Poe Lock and see it in action.