Is Duluth the farthest-inland port in North America?

These days, it takes about a week for a ship to sail from the Atlantic Ocean to Duluth, a 2,342-mile journey winding through the St. Lawrence Seaway and Great Lakes to the western tip of Lake Superior.

The Port of Duluth-Superior serves as a transportation epicenter, connecting railroads and interstates with the marine "highway" used to ferry millions of tons of cargo around the world. Duluth-Superior is the 19th-largest U.S. port in terms of tonnage handled, according to the U.S. Army Corps of Engineers — a rather unusual feat for a shipping hub located in the landlocked Midwest.

This piqued the interest of one reader, who wondered: Is Duluth the farthest inland port in North America? The query is the latest in the Star Tribune's Curious Minnesota series, a community-driven reporting project fueled by great questions from readers.

It wasn't until the St. Lawrence Seaway opened in 1959 that the Twin Ports welcomed their first large ship from the Atlantic. Before that, only ships smaller than 260 feet in length could reach the Great Lakes from the ocean, according to the Duluth Seaway Port Authority.

"Without the opening of the St. Lawrence Seaway, the Port of Duluth-Superior would not be the world port that it is," said Jayson Hron, spokesperson for the Port Authority.

The Seaway ushered in what then-President Dwight Eisenhower proclaimed would be "a new era" for Duluth. In the spring of 1959, thousands gathered to cheer the Ramon de Larrinaga, a 475-foot vessel from England, as it sailed beneath the steel trusses of the city's iconic Aerial Lift Bridge.

Eisenhower's prediction turned out to be true. By the end of the 1959 shipping season, 235 ocean vessels — nicknamed "salties" — had passed through the port, in addition to the standard batch of freshwater freighters known as "lakers," according to the Port Authority.

So, the short answer seems to be yes — if you're looking for the North American seaport farthest from the sea, Duluth-Superior has claimed the title. The U.S. Coast Guard's website and the World Port Source's maps of the continent's waterways support the port's assertion. Among the ports situated on America's lakes, rivers and canals, Duluth-Superior is arguably the busiest, in terms of cargo.

On many days, more than a dozen ships float in and out of the port's harbor carrying tons of iron ore, limestone, grains and coal. A single 1,000-foot vessel can carry the equivalent of 2,340 trucks, Hron said.

During the 2018 shipping season, the Port of Duluth-Superior handled 35.9 million tons of cargo, "far and away" the largest total amount of goods loaded and unloaded at any port on the Great Lakes, he added.

The Ports of Cincinnati-Northern Kentucky technically handle more goods than Duluth-Superior, according to the Army Corps of Engineers, but those "ports" cover a 226-mile stretch of river running through 15 counties in Ohio and Kentucky.

"I don't know that people have always realized all that's happening here on the working waterfront," Hron said. "They don't realize their cellphone isn't in their hand without iron ore from Minnesota and Great Lakes shipping."