When most Canadians think about shipping, they picture massive ocean-going container ships crossing the Atlantic or Pacific. However, one of the world’s most important commercial shipping systems lies entirely within North America.
Stretching nearly 3,700 kilometres from the western shores of Lake Superior to the Atlantic Ocean, the Great Lakes marine transportation system has served as Canada’s industrial backbone for over two centuries. Before railways crossed the country and before modern highways existed, ships on the Great Lakes transported people, grain, lumber, coal, iron ore and manufactured goods between growing settlements.
Today, the Great Lakes shipping industry remains an essential part of Canada’s economy, moving hundreds of millions of tonnes of cargo annually while connecting Canadian manufacturers, mines, farms and ports with both domestic and international markets.
This vast freshwater transportation network is one of the safest, most environmentally friendly and cost-effective ways to move bulk commodities across North America.
The Five Great Lakes
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The Great Lakes form the largest connected body of fresh water on Earth by surface area, containing approximately 20% of the world’s surface fresh water.
The system consists of:
| Lake | Surface Area | Maximum Depth |
|---|---|---|
| Lake Superior | 82,100 km² | 406 m |
| Lake Michigan | 58,000 km² | 281 m |
| Lake Huron | 59,600 km² | 229 m |
| Lake Erie | 25,700 km² | 64 m |
| Lake Ontario | 18,960 km² | 244 m |
Together they border:
- Ontario
- Minnesota
- Wisconsin
- Illinois
- Indiana
- Michigan
- Ohio
- Pennsylvania
- New York
Nearly 40 million people live within the Great Lakes Basin, making it one of the largest concentrations of population and industry in North America.
Why Water Transportation Matters
Moving cargo by ship is remarkably efficient.
One large lake freighter can carry the equivalent of:
- More than 900 transport trucks
- Around 300 rail cars
- Tens of thousands of tonnes of bulk cargo
Because water creates far less rolling resistance than roads or railways, ships require significantly less fuel per tonne of cargo transported.
This means marine transportation generally offers:
- Lower greenhouse gas emissions per tonne moved
- Reduced highway congestion
- Lower transportation costs
- Greater efficiency for heavy commodities
For industries moving iron ore, coal, limestone, salt or grain, ships remain the most economical transportation option.
A History of Great Lakes Shipping
Indigenous Transportation
Long before European settlement, Indigenous peoples used the Great Lakes as natural highways.
Birchbark canoes travelled thousands of kilometres carrying:
- Fur
- Copper
- Food
- Stone tools
- Trade goods
Complex trading networks linked communities across much of present-day Canada centuries before European arrival.
The Fur Trade Era
During the 1600s and 1700s, French explorers and fur traders expanded water transportation throughout the Great Lakes.
Cargo included:
- Beaver pelts
- Canoes
- Food supplies
- Trade goods
- Military equipment
Major trading posts grew into settlements that eventually became cities including:
- Toronto
- Kingston
- Detroit
- Sault Ste. Marie
Steamships Change Everything
The arrival of steam-powered vessels during the nineteenth century transformed Great Lakes commerce.
Unlike sailing ships, steamships could:
- Maintain schedules
- Carry heavier cargo
- Travel regardless of wind conditions
- Extend the shipping season
As Canada’s industrial revolution accelerated, shipping volumes increased dramatically.
Iron mines, forests, grain elevators and factories all depended on reliable marine transportation.
The Birth of Canadian Lake Freighters
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Modern Great Lakes freighters are engineering marvels.
Unlike ocean-going container ships, most lake vessels specialize in moving bulk commodities.
Many Canadian ships feature self-unloading systems, allowing them to unload thousands of tonnes of cargo without requiring extensive shore equipment.
A conveyor belt system running beneath the cargo holds carries material to a long unloading boom capable of placing cargo directly onto docks or into storage facilities.
This innovation dramatically reduced unloading times and labour costs.
What Cargo Moves Across the Great Lakes?
The Great Lakes primarily transport bulk commodities that support manufacturing and heavy industry.
Iron Ore
Iron ore mined in northern Ontario, Minnesota and Michigan supplies steel mills throughout Canada and the United States.
Without Great Lakes shipping, North America’s steel industry would face dramatically higher transportation costs.
Grain
Prairie grain reaches Great Lakes ports primarily by rail before being loaded onto ships.
Common cargoes include:
- Wheat
- Corn
- Soybeans
- Canola
- Barley
- Oats
Many shipments continue toward overseas export markets.
Limestone
Limestone is essential for:
- Cement production
- Steel manufacturing
- Construction
- Agriculture
Canadian quarries around Georgian Bay and Lake Huron produce millions of tonnes annually.
Salt
Ontario’s underground salt mines, including those beneath Lake Huron, produce road salt distributed throughout eastern North America.
Large lake freighters move salt to ports before trucks complete final delivery.
Coal
Although coal shipments have declined as electricity generation changes, it remains an important cargo for certain industrial users and steel production.
Cement
Finished cement products move between manufacturing plants and construction markets throughout the Great Lakes region.
Petroleum Products
Refined fuels including gasoline, diesel and other petroleum products move between refineries and distribution terminals.
Wind Turbine Components
Increasingly, oversized renewable energy equipment travels by ship because road transportation is often impractical.
Canada’s Major Great Lakes Ports
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Canada operates numerous commercial ports throughout the Great Lakes.
Among the busiest are:
Thunder Bay
Known as Canada’s premier grain export port, Thunder Bay serves as the eastern gateway for Prairie grain entering the Great Lakes system.
Hamilton
Hamilton is Canada’s busiest port on the Great Lakes by cargo volume.
Its industries include:
- Steel
- Construction materials
- Petroleum
- Agricultural products
- Manufacturing inputs
Windsor
Located opposite Detroit, Windsor handles steel, aggregates, salt and other industrial cargoes while supporting cross-border trade.
Oshawa
Oshawa increasingly handles project cargo, steel products, construction materials and agricultural shipments.
Sault Ste. Marie
Located between Lake Superior and Lake Huron, this strategic port supports steel production and international shipping.
The Canadian Shipping Fleet
Canada’s domestic fleet is dominated by specialized companies operating self-unloading vessels.
These ships transport cargo almost continuously during the navigation season.
Many vessels exceed:
- 220 metres in length
- 30 metres in width
- 35,000 tonnes of cargo capacity
Several ships are specifically designed to fit through locks and canals connecting the lakes.
Unlike ocean shipping, Great Lakes navigation depends heavily on weather.
The shipping season generally runs from:
Late March through late December
Winter ice often closes portions of the system.
The Canadian Coast Guard operates icebreakers to extend navigation where possible, but many vessels undergo annual maintenance during winter lay-up.
Modern weather forecasting and ice management have helped lengthen operational seasons compared to the past.
The Welland Canal
One of the greatest engineering achievements in Canadian history, the Welland Canal allows ships to bypass Niagara Falls by lifting or lowering them nearly 100 metres between Lake Ontario and Lake Erie.
Without the canal, commercial navigation between the upper Great Lakes and Lake Ontario would be impossible.
The canal is one of the critical links connecting the Great Lakes transportation network.
Environmental Benefits
Marine shipping produces significantly fewer greenhouse gas emissions per tonne-kilometre than trucking and is among the most fuel-efficient modes of freight transportation.
Additional environmental benefits include:
- Reduced highway congestion
- Lower road maintenance costs
- Reduced accident rates
- Lower overall fuel consumption
- Efficient movement of heavy cargo
However, the industry also faces environmental challenges, including managing ballast water to reduce the spread of invasive species and improving air emissions from older vessels.
Economic Importance
The Great Lakes shipping industry supports:
- Mining
- Agriculture
- Manufacturing
- Steel production
- Construction
- Energy generation
- International trade
It also supports thousands of direct and indirect jobs, including:
- Ship crews
- Port workers
- Marine engineers
- Pilots
- Shipbuilders
- Mechanics
- Longshore workers
- Logistics specialists
Entire industrial supply chains depend on reliable marine transportation.
Challenges Facing the Industry
Despite its importance, the Great Lakes shipping industry faces several ongoing challenges.
Aging Infrastructure
Many locks, bridges and port facilities require modernization to improve reliability and accommodate future trade growth.
Climate Change
Fluctuating lake levels, changing ice conditions and more frequent severe weather events create operational challenges.
Labour Shortages
Like many transportation sectors, recruiting skilled marine personnel remains an industry concern.
Competition
Rail and trucking continue competing for certain cargoes, particularly higher-value freight requiring faster delivery.
Invasive Species
Ballast water introduced invasive species such as zebra mussels and quagga mussels into the Great Lakes, affecting ecosystems and infrastructure. Ongoing regulations aim to reduce the risk of further introductions.
Looking Ahead
The future of Great Lakes shipping will likely include:
- Cleaner propulsion systems
- Alternative fuels
- Greater automation
- Improved navigation technologies
- Modernized ports
- Expanded intermodal connections
As governments seek to reduce transportation-related emissions, marine shipping is expected to remain an important component of a more sustainable freight network.
The Gateway to the Atlantic
The Great Lakes alone would form an extraordinary inland transportation system.
Yet for much of history, ships travelling these waters could go no farther than the natural barriers separating the lakes from the Atlantic Ocean. Rapids, waterfalls and elevation changes prevented continuous navigation between the heart of North America and global markets.
The solution was one of the largest engineering achievements ever undertaken jointly by Canada and the United States: a system of canals, locks and channels that transformed inland shipping forever.
That project became the St. Lawrence Seaway.
In our next article, we’ll explore how the St. Lawrence Seaway was conceived, built and expanded, the engineering challenges it overcame, its profound impact on communities and industries, and why it remains one of Canada’s most strategically important transportation corridors.
Sources
The information in this article is based on data and publications from:
- Transport Canada
- Statistics Canada
- The Great Lakes–St. Lawrence Seaway System
- The St. Lawrence Seaway Management Corporation
- The Chamber of Marine Commerce
- Environment and Climate Change Canada
- Canadian Coast Guard
- Natural Resources Canada
- The Canadian Encyclopedia
These organizations regularly publish statistics, historical information and technical reports relating to Canadian marine transportation, Great Lakes commerce and inland shipping.
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