The Great Lakes Highway: A History of Commerce on North America’s Inland Seas

Long before interstate highways, railroads or commercial aviation, North America possessed a natural transportation system of almost unimaginable size. The five Great Lakes—Ontario, Erie, Huron, Michigan and Superior—formed an inland maritime highway reaching deep into the continent.

Together with the rivers, portage trails, canals and locks that connected them, the lakes carried the materials that built the industrial United States and Canada. Grain moved east from farms across the Midwest and Canadian Prairies. Coal moved north and west from Appalachian mining districts. Iron ore traveled south and east from Minnesota, Michigan, Wisconsin, Quebec and Labrador. Lumber, copper, salt, limestone, manufactured goods, machinery and passengers also moved through the system.

The Great Lakes did not become an industrial highway because one person suddenly invented the idea. The system evolved over centuries. Indigenous nations first developed and maintained the trade routes. French explorers and fur traders expanded commercial travel across them. British and American merchants built larger vessels and ports. Canal promoters found ways around waterfalls and rapids. Finally, mining companies, railroads, steel producers and shipbuilders transformed the lakes into one of the most productive bulk-freight corridors in the world.

The St. Lawrence Seaway, opened in 1959, was the latest major chapter in that history—not its beginning.

An Ancient Transportation Network

The Great Lakes were a commercial highway thousands of years before Europeans arrived. Indigenous peoples traveled by canoe along the lakes, rivers and tributaries, carrying food, tools, copper, stone, pottery and other goods between communities.

These waterways were not isolated wilderness routes. They formed an extensive network of established travel corridors. Portage trails connected rivers flowing in different directions and allowed canoes and cargo to be carried around waterfalls, rapids and stretches of shallow water.

One of the most important routes crossed what is now central New York. Travelers could move from the Hudson River into the Mohawk River, cross the Oneida Carry between the Mohawk and Wood Creek, continue through Oneida Lake and the Oswego River, and reach Lake Ontario. The National Park Service describes the Oneida Carry as an ancient transportation link used for thousands of years to move people, trade goods and information between the Atlantic watershed and the Great Lakes.

The Haudenosaunee Confederacy occupied a strategically important position along these routes. Other Indigenous nations—including the Anishinaabe, Odawa, Ojibwe, Potawatomi, Wyandot and many others—maintained their own commercial and diplomatic networks throughout the Great Lakes region.

The first Great Lakes highway was therefore not created by European governments or industrial corporations. It was inherited from Indigenous geography, knowledge and transportation systems.

The French Fur-Trade Era

During the 1600s and 1700s, French explorers, missionaries and fur traders entered the Great Lakes by following Indigenous routes and relying heavily upon Indigenous guides, alliances and canoe technology.

The St. Lawrence River provided access from the Atlantic to Montreal, but the river above Montreal contained rapids that prevented uninterrupted navigation by larger vessels. Cargo had to be transferred into canoes or smaller craft and carried around difficult sections.

From Montreal, trading expeditions moved west through the Ottawa River system or continued toward Lake Ontario and the upper lakes. French posts were established at strategic locations including Niagara, Detroit, Michilimackinac and Sault Ste. Marie.

Furs—especially beaver pelts—were the principal commercial cargo moving east. European metal goods, firearms, cloth, tools, alcohol and manufactured products moved west. Canoes carried surprisingly large loads, but the system remained labor-intensive. Every major rapid or height of land meant unloading, carrying and reloading cargo.

Military supplies also traveled along the same routes. Control of the Great Lakes became strategically important during the colonial wars between France and Britain and later during the American Revolution and the War of 1812.

The lakes were already a continental trade route, but they were still divided by natural obstacles.

Ships on the Inland Seas

As settlements and military posts grew, shipbuilders constructed increasingly large sailing vessels on the lakes. Schooners became the workhorses of early Great Lakes commerce.

These ships carried flour, grain, lumber, potash, salt, furs, military supplies, immigrants and general merchandise. Because the lakes are enormous bodies of water capable of producing severe storms and high waves, Great Lakes sailors developed a distinct maritime culture resembling that of ocean ports.

Navigation remained dangerous. Early charts were incomplete, harbors were poorly marked and many coastlines lacked dependable lights. Vessels could be lost to storms, fire, collision, grounding or shifting cargo.

Despite the hazards, sailing ships offered an enormous advantage over land transportation. Before dependable canals and railroads, moving heavy cargo by wagon was slow and expensive. A vessel could carry in one trip what might otherwise require dozens or hundreds of wagons.

By the early 1800s, merchants and political leaders increasingly understood that the Great Lakes could become the economic interior of North America—provided they could connect the lakes to the Atlantic and eliminate the natural barriers separating one lake from another.

The Problem of Niagara Falls

The greatest obstacle between the lower and upper Great Lakes was Niagara Falls.

A vessel arriving at the western end of Lake Ontario could not simply continue into Lake Erie. Freight had to be unloaded near the Niagara River, transported overland around the falls and loaded aboard another vessel above the escarpment.

This expensive interruption prevented the lakes from functioning as one continuous commercial system.

The man most closely associated with solving that problem was William Hamilton Merritt, a businessman and mill owner in Upper Canada. Merritt initially proposed a canal in 1818 to bring water to his mills. The plan expanded into a much more ambitious project connecting Lake Ontario with Lake Erie. He organized support, helped establish the Welland Canal Company and traveled extensively to raise financing.

The first Welland Canal opened in 1829. It allowed vessels and cargo to bypass Niagara Falls through a system of artificial channels and locks.

The original canal was much smaller and less dependable than the modern Welland Canal, and it was rebuilt and enlarged several times. Nevertheless, it fundamentally changed Great Lakes commerce. For the first time, a navigable canal connected Lake Ontario with Lake Erie.

The Erie Canal and New York’s Commercial Revolution

While Canadian interests were working around Niagara Falls, New York was building a connection between Lake Erie and the Hudson River.

The idea of linking the Hudson with the Great Lakes had circulated for years. The Hudson and Mohawk valleys offered a rare natural passage through the Appalachian barrier. Early improvement companies attempted to make the Mohawk, Wood Creek and associated waterways more navigable, but those projects remained limited.

New York Governor DeWitt Clinton became the leading political champion of a full canal. Critics mocked the proposal as “Clinton’s Folly” or “DeWitt’s Ditch,” but construction began in 1817.

The Erie Canal opened in 1825, connecting the Hudson River at Albany with Lake Erie at Buffalo. The canal transformed New York and the American interior. It allowed agricultural goods and raw materials from the Great Lakes region to travel east to New York City, while immigrants and manufactured products moved west.

The Erie Canal did not permit large lake vessels to sail directly to Manhattan. Cargo was transferred at Buffalo into smaller canal boats, carried across New York and transferred again to Hudson River vessels. Even with those transfers, the route dramatically reduced shipping costs and travel time.

Buffalo became one of the continent’s great transfer ports. Grain elevators, warehouses, docks, rail yards, flour mills and shipping offices appeared along its waterfront. New York City gained direct commercial access to the developing Midwest and emerged as the leading American port and financial center.

The canal also accelerated settlement, land speculation and industrial development. It came with a serious human cost, including the displacement and dispossession of Indigenous communities whose territories and older transportation routes made the project possible.

The Canadian Canal Route

Canada developed its own route between the Great Lakes and the Atlantic.

The Lachine Rapids near Montreal had long prevented large vessels from traveling continuously between the upper St. Lawrence and Montreal. The Lachine Canal, completed in 1825, bypassed those rapids and became the first link in a developing Canadian canal system between Montreal and the Great Lakes.

Additional canals were constructed along the St. Lawrence to avoid other rapids. These included early canals near Cornwall, Williamsburg and other locations. Like the first Welland Canal, they were relatively narrow and shallow and required cargo to be carried in vessels built to fit the locks.

Before the modern Seaway, large upper-lake vessels generally could not sail directly to the Atlantic Ocean. Grain and other cargoes were often transferred into smaller vessels capable of passing through the Canadian canals. At Montreal or another lower-river port, cargo might be transferred again into oceangoing ships.

This repeated unloading and reloading created an entire industry of elevators, warehouses, freight handlers, tugboats and forwarding companies.

Opening Lake Superior: The Soo Locks

Another major obstacle existed at Sault Ste. Marie, where the St. Marys River drops between Lake Superior and Lake Huron.

The rapids prevented large vessels from passing freely between the upper and lower lakes. Cargo and boats had to be portaged around the rapids.

A small lock had been constructed on the Canadian side during the fur-trade era, but American forces destroyed it during the War of 1812. For decades afterward, cargo continued to be carried around the rapids.

The discovery and development of copper and iron deposits around Lake Superior created intense pressure for a dependable canal. Michigan granted land to a private company, and the first American state locks opened in 1855.

The St. Marys Falls Canal—better known as the Soo Locks—overcame the approximately 21-foot difference in water level between Lake Superior and the lower Great Lakes. Its completion effectively opened Lake Superior to large-scale commercial shipping and helped unlock the region’s copper, timber and iron resources.

The federal government later assumed control of the locks and repeatedly enlarged them. The Soo became one of the most strategically important transportation points in North America.

Lumber, Wheat and Early Bulk Cargoes

During the middle decades of the 1800s, lumber and grain became dominant cargoes.

The forests of Michigan, Wisconsin, Minnesota and Ontario supplied building material for rapidly growing cities. Logs could be floated down rivers, assembled into rafts or loaded aboard schooners and steam vessels. Finished lumber moved to Chicago, Detroit, Cleveland, Buffalo and smaller ports throughout the region.

Agricultural settlement created another enormous trade. Wheat, corn and other grains moved from farms to local elevators, then into lake vessels.

Buffalo’s grain elevators mechanized the unloading and transfer process. Steam-powered equipment lifted grain from ships, stored it in tall bins and released it into canal boats or railroad cars. Similar elevator systems appeared in Chicago, Milwaukee, Duluth, Thunder Bay and other ports.

The Great Lakes became the principal route by which the agricultural wealth of the interior reached eastern cities and overseas markets.

Steam Power Changes the Lakes

The first Great Lakes steamboats appeared during the early 1800s. Steam propulsion allowed vessels to move without depending entirely upon favorable winds.

Early steamships often carried passengers, mail, packaged freight and immigrants. Their cabins and scheduled service helped connect communities around the lakes.

Sailing vessels remained economical for bulk cargo because they did not need to carry fuel. Schooners continued operating alongside steamships for much of the 19th century. Some were towed by powered vessels in long lines.

Over time, propulsion machinery improved and coal-fired steam vessels became more efficient. Shipbuilders began combining the cargo capacity of sailing ships with steam engines, producing vessels sometimes known as steam barges or steam schooners.

The evolution from wood to iron and then steel construction allowed ships to become longer, stronger and capable of carrying much larger loads. Great Lakes iron and steel freighters grew rapidly during the late 1800s, from vessels under 300 feet to ships of 400 and 500 feet and eventually beyond 600 feet.

Iron Ore and the Rise of the American Steel Industry

Iron ore eventually became the cargo most closely associated with Great Lakes shipping.

Ore deposits in Michigan’s Upper Peninsula and later the Mesabi Range of Minnesota were located far from the coalfields and industrial centers that converted ore into iron and steel. The lakes provided the missing transportation link.

Railroads carried ore from mines to loading docks at ports such as Duluth, Two Harbors, Superior, Marquette and Escanaba. At the docks, ore cars were elevated above the ships and emptied into storage pockets. Chutes then released the ore into cargo holds.

Freighters carried the ore down the lakes and through the Soo Locks to steel-producing centers around Lake Michigan and Lake Erie. Major receiving ports included Gary, Chicago, Detroit, Toledo, Cleveland, Lorain, Ashtabula, Conneaut and Buffalo.

The lake route helped create an integrated industrial system. Iron ore moved south and east. Coal from Pennsylvania, Ohio and West Virginia moved north and west to fuel furnaces, factories and power plants. Limestone used in steelmaking also traveled by lake.

The Great Lakes thus connected the ingredients of industrial production: iron ore from the north, coal from the Appalachian region and manufacturing plants located near major population centers.

The ore trade supported the expansion of the American steel industry and the growth of railroads, bridges, skyscrapers, automobiles, machinery, weapons and countless manufactured products. Historic ore docks at Marquette and other ports remain monuments to the connection between Great Lakes shipping and American steel production.

Coal Moves in the Opposite Direction

Coal was the natural return cargo for many vessels.

After unloading iron ore at a lower-lake industrial port, a ship could load coal for delivery to cities, railroads, factories and power plants farther west or north.

This two-directional movement improved the economics of shipping. Rather than returning empty, vessels could carry coal toward Lake Superior ports and bring ore back down.

Coal fueled steamships themselves, powered factories, heated buildings and supplied railroads. Coke, produced from coal, was required for blast furnaces.

The image of a Great Lakes freighter hauling ore in one direction and coal in another became a defining feature of the industrial waterway.

The Lake Freighter Is Reengineered

The classic Great Lakes bulk freighter developed specifically for this trade.

Its pilothouse and crew accommodations were traditionally placed at the bow, while the engine room and smokestack were located at the stern. Between them stretched a long cargo section fitted with multiple hatches.

This arrangement maximized cargo capacity and allowed ore, coal, grain or stone to be distributed throughout the vessel.

The first large steel bulk carriers established a pattern that would dominate the lakes for generations. Later vessels introduced self-unloading equipment. A self-unloader could discharge cargo using onboard conveyor belts and a long boom, reducing dependence upon shore-based unloading machinery.

The lakes also encouraged standardized ship dimensions. Vessels were designed around the sizes of locks, canals and harbor channels. A ship that was too long, wide or deep could not pass through a particular part of the system.

This produced the distinction between “lakers,” designed primarily for Great Lakes service, and “salties,” oceangoing vessels capable of entering the lakes through the St. Lawrence system.

Grain Goes East

Grain remained one of the Great Lakes system’s most important eastbound cargoes.

Wheat from the American Midwest and Canadian Prairies traveled by rail to ports including Duluth, Superior, Milwaukee, Chicago, Toledo and Thunder Bay. Grain elevators stored, blended and loaded the crop into ships.

Before the modern Seaway, upper-lake grain was frequently unloaded into elevators at Buffalo, Port Colborne, Kingston, Prescott or other transfer points. It was then moved through canals, by rail or aboard smaller river vessels toward Montreal and the Atlantic.

The grain trade linked inland farms to bakeries and consumers in the eastern United States, Canada, Europe and beyond. It also supported a financial and commercial network of grain exchanges, insurers, brokers, banks, railroads and inspection services.

Passenger Ships and Package Freighters

Not everything moved in enormous piles of ore or grain.

Passenger steamers connected cities and resort communities throughout the lakes. Travelers boarded vessels for regular service between ports, sightseeing excursions and vacations.

Package freighters carried mixed cargoes rather than a single bulk commodity. Their manifests could include farm equipment, automobiles, household goods, food, mail and manufactured products.

Railroads also operated fleets of ships. Railroad car ferries carried loaded railcars across the lakes, eliminating the need to route trains around the shoreline. Other vessels transported passengers and freight as extensions of railroad service.

Before highways and commercial aviation became dominant, the lakes were a major passenger transportation system as well as a freight network.

Shipwrecks and the Cost of Commerce

The Great Lakes highway was productive, but it was never gentle.

Violent storms, sudden fog, ice, shallow channels and rocky shorelines claimed thousands of vessels. Ships foundered after taking on water, broke apart in heavy seas, burned, collided or ran aground.

November storms became especially feared. Late-season vessels sometimes sailed heavily loaded while cold air, warm lake water and powerful weather systems produced extreme conditions.

Navigation gradually became safer through improved charts, lighthouses, lifesaving stations, weather forecasting, radio communications, radar and stricter construction standards. Dredging projects deepened channels, while breakwaters created protected harbors.

The shipwrecks resting beneath the lakes document the entire development of inland navigation—from small schooners and early steamships to giant industrial bulk carriers. NOAA describes the wrecks within the Thunder Bay National Marine Sanctuary as a nearly complete collection of Great Lakes vessel types.

Before the St. Lawrence Seaway

By the early 20th century, the Great Lakes were already an industrial transportation powerhouse.

The Erie Canal and later New York State Barge Canal connected the lakes with the Hudson River. The Welland Canal connected Lakes Ontario and Erie. The Soo Locks connected Lake Superior with the lower lakes. Canadian canals carried vessels around St. Lawrence River rapids.

However, the system still lacked a deep, continuous navigation channel capable of allowing many oceangoing ships to travel directly between the Atlantic and the industrial heartland.

Cargo often required transshipment. A large lake freighter could carry grain or ore to a transfer port, but its size prevented it from passing through the older locks. Smaller “canallers” or river vessels completed the next stage of the journey.

Supporters of a deeper international waterway argued that the Great Lakes should be opened directly to world commerce. Proposals appeared repeatedly during the late 19th and early 20th centuries.

The project faced political opposition, financial concerns and competition from railroads and Atlantic ports. The United States and Canada also had to negotiate control, construction costs, hydroelectric development and international boundary issues.

Building the St. Lawrence Seaway

After decades of debate, the United States and Canada agreed to proceed with the modern St. Lawrence Seaway.

Construction required new locks, channels, dams and power projects along the St. Lawrence River. Communities were relocated, land was flooded and older sections of the river were permanently transformed.

The Seaway opened to commercial navigation in 1959. It allowed ships built to Seaway dimensions to travel between the Atlantic Ocean and the Great Lakes through a system of locks and deepened channels.

The Seaway did not replace the older Great Lakes highway. It completed and enlarged it.

Iron ore, grain, coal, coke, steel, stone, salt, chemicals, machinery and manufactured goods moved through the new system. The waterway connected approximately 2,300 miles of inland navigation from the Atlantic to the western end of Lake Superior. Great Lakes cities that had begun as trading posts were now part of an international marine corridor.

The Industrial Cities Built by Water

Many of the great industrial cities of the Midwest and Ontario owe their development to Great Lakes transportation.

Chicago became a railroad, meatpacking, manufacturing and grain-distribution center. Detroit developed into an automobile capital with access to iron, steel, coal and other raw materials. Cleveland became a major ore-receiving, steelmaking and manufacturing center. Milwaukee handled grain, machinery and manufactured goods. Duluth and Superior became gateways to the mineral and agricultural wealth of the upper Midwest.

Buffalo became the point where Great Lakes cargo met the Erie Canal, railroads and eastern markets. Hamilton developed into a Canadian steel center. Toronto grew as a commercial port and industrial city. Thunder Bay became an important grain-export and transshipment point.

Smaller ports also played specialized roles. Some shipped stone, salt, lumber or grain. Others received coal, petroleum products, road salt or construction materials.

The prosperity of the Great Lakes region was not merely located beside the water. It was created by the ability to move heavy materials across that water cheaply and efficiently.

The Great Lakes Highway Today

The cargo mix has changed, but the Great Lakes–St. Lawrence system remains active.

Iron ore continues to move to steel plants. Grain travels toward domestic and overseas markets. Limestone, cement, salt, coal, coke, steel products, aggregates, machinery and project cargo move between regional ports.

Modern vessels are larger, more automated and operated by smaller crews than their predecessors. Many bulk carriers can unload themselves. Ports connect marine transportation with railroads, highways, pipelines and industrial facilities.

The system remains especially valuable for heavy, bulky cargoes that would be expensive to move entirely by truck or rail.

Commercial navigation is seasonal in many parts of the system because winter ice closes locks and restricts shipping. Each spring, the navigation season begins again, continuing a commercial rhythm that has shaped the region for generations.

More Than a Shipping Route

The Great Lakes highway is not merely a collection of shipping lanes. It is one of the central organizing forces in North American history.

It influenced where cities were founded, where railroads were built, where factories operated and where immigrants settled. It helped New York City become a global port, turned Chicago and Detroit into industrial giants and connected the mineral wealth of Lake Superior with the factories of the lower lakes.

It also produced environmental and cultural consequences. Canal construction altered watersheds and assisted the spread of invasive species. Industrial pollution damaged rivers, harbors and shorelines. Large projects displaced Indigenous peoples and later removed entire communities along the St. Lawrence.

The history is therefore both a story of extraordinary engineering and a reminder that progress always sends somebody the invoice.

What began as a network of Indigenous canoe routes became a fur-trade corridor, a sailing-ship highway, a canal system and finally an industrial transportation network linking the center of the continent with the Atlantic Ocean.

The St. Lawrence Seaway may be the best-known name attached to that network today, but the Great Lakes had already been carrying the commerce of nations for centuries before the first modern Seaway lock opened.

About the Historical Film

The accompanying educational film, preserved and presented by TravelFilmArchive, examines the Great Lakes as an industrial transportation highway. It shows how iron ore, coal, grain and other essential materials moved between mines, farms, ports and manufacturing cities.

The film captures an era when the connection between shipping and industrial prosperity was visible everywhere along the lakes: ore docks towering above freighters, grain elevators lining the waterfront, coal piles feeding factories and enormous ships carrying the physical ingredients of the American economy.

Clean DVD or digital copies for personal home or educational use may be available by contacting Archive Farms at questions@archivefarms.com. Commercial footage licensing information is available through TravelFilmArchive.