Great Lakes Nautical Charts

Great Lakes nautical charts: planning navigation between the United States and Canada

The North American Great Lakes form one of the world's largest navigable freshwater systems. Located along the border between the United States and Canada, they comprise five major lakes: Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario. Connected by rivers, straits, canals and locks, they form an extensive inland waterway network accessible from the Atlantic Ocean via the St. Lawrence River.

Great Lakes nautical charts are essential for planning passages, identifying depths, navigating port approaches and travelling through the region's numerous channels. They are indispensable for recreational boaters, professional mariners, fishermen and commercial vessels using the St. Lawrence Seaway.

Despite their inland location, the Great Lakes present navigation conditions comparable to those encountered on some inland seas. Long distances, strong winds, short, steep waves and seasonal variations in water levels require careful preparation.

The five Great Lakes: an extensive inland navigation network

The Great Lakes system comprises five interconnected bodies of water:

• Lake Superior, the largest and deepest of the Great Lakes.

• Lake Michigan, located entirely within the United States.

• Lake Huron, connected to Lake Michigan by the Straits of Mackinac.

• Lake Erie, known for its relatively shallow waters and significant maritime traffic.

• Lake Ontario, which connects to the St. Lawrence River.

Together, these lakes form a major transportation route between North America's industrial regions and the Atlantic Ocean. The St. Lawrence Seaway allows ocean-going vessels to reach ports deep within the continent.

Which nautical charts should you choose for navigating the Great Lakes?

Great Lakes nautical chart coverage includes several categories of charts suited to different stages of navigation.

• General charts: covering an entire lake or several basins, allowing navigators to plan long-distance passages.

• Coastal charts: showing depths, shoals, islands and navigational hazards near shore.

• Approach charts: facilitating access to ports, bays and navigable channels.

• Harbour plans: providing detailed representations of quays, harbour basins, anchorage areas and port facilities.

• Canal and inland waterway charts: helping navigators prepare for lock passages and journeys between the different lakes.

The appropriate chart scale depends on the type of navigation, the vessel's draught and the intended route.

Lake Superior: offshore navigation on the largest Great Lake

Lake Superior extends across the United States and Canada. Its considerable size and sometimes challenging weather conditions require preparation comparable to offshore navigation at sea.

Its principal ports include Duluth, Superior, Thunder Bay, Marquette and Sault Ste. Marie.

Lake Superior nautical charts help identify numerous bays, islands, shoals and commercial shipping routes used by bulk carriers transporting iron ore, grain and other commodities.

The approaches to the Apostle Islands, Isle Royale and Thunder Bay require detailed chart coverage.

Lake Michigan: from Chicago to the Straits of Mackinac

Located entirely within the United States, Lake Michigan is an important destination for recreational boating and commercial shipping.

Its principal ports include Chicago, Milwaukee, Green Bay, Muskegon and Traverse City.

Lake Michigan nautical charts help prepare passages between the shores of Wisconsin, Illinois, Indiana and Michigan.

Navigation in Green Bay, the approaches to Chicago and the Straits of Mackinac requires particular attention to depths, channels and maritime traffic.

Lake Michigan connects to Lake Huron through the Straits of Mackinac, a strategic passage between the two basins.

Lake Huron and Georgian Bay

Lake Huron extends between the US state of Michigan and the Canadian province of Ontario.

It includes several remarkable cruising areas, notably Georgian Bay, the North Channel and the approaches to Manitoulin Island.

Its principal ports include Port Huron, Alpena, Sarnia, Goderich and Collingwood.

Lake Huron nautical charts are particularly important in areas containing numerous islands, reefs and narrow passages.

Georgian Bay and the North Channel are renowned for their scenery and cruising routes, but require detailed charts because of their complex coastlines.

Lake Erie: navigating between industrial ports and recreational boating areas

Lake Erie is the shallowest of the five Great Lakes. Its relatively shallow waters can contribute to the formation of short, steep waves when winds strengthen.

Its principal ports include Detroit, Toledo, Cleveland, Erie and Buffalo, as well as Windsor and Port Colborne on the Canadian side.

Lake Erie nautical charts help identify commercial shipping channels, shoals, islands and port approaches.

The areas around Pelee Island, the Bass Islands and Sandusky Bay require particularly accurate chart coverage.

Lake Erie connects to Lake Ontario through the Welland Canal, which allows vessels to bypass Niagara Falls.

Lake Ontario and the St. Lawrence Seaway

Lake Ontario is the easternmost of the Great Lakes and provides the connection to the St. Lawrence River.

Its principal ports include Toronto, Hamilton, Kingston, Rochester and Oswego.

Lake Ontario nautical charts help prepare passages between the United States and Canada, as well as approaches to major commercial ports.

At its eastern end, the Thousand Islands region marks the entrance to the St. Lawrence River. This area contains numerous islands, narrow channels and navigation areas requiring detailed charts.

The St. Lawrence Seaway then provides access to Montreal, Quebec City, the Gulf of St. Lawrence and the Atlantic Ocean.

NOAA, the Canadian Hydrographic Service and nautical chart publishers

Two major official hydrographic services provide nautical chart coverage of the Great Lakes.

The NOAA (National Oceanic and Atmospheric Administration) produces official nautical charts of US waters. Its electronic navigational charts (ENCs) cover all five Great Lakes, their port approaches and the principal navigable waterways.

The Canadian Hydrographic Service (CHS) produces official charts of Canadian waters, including Lakes Superior, Huron, Erie and Ontario, as well as the St. Lawrence River. It provides both paper charts and electronic navigational charts.

Other publishers, including Garmin Navionics and C-MAP, offer digital charting solutions covering the Great Lakes, depending on the geographical area and compatible equipment.

Specific navigation conditions on the Great Lakes

The Great Lakes present several characteristics that distinguish them from traditional maritime environments.

The absence of significant ocean tides does not mean that water levels remain constant. Seasonal variations, winds and seiche phenomena can cause substantial changes.

Strong winds can also generate short, difficult seas, particularly on Lakes Erie and Superior.

During winter, ice formation severely restricts navigation in several areas.

Commercial vessels, ferries, locks and narrow channels also require particular vigilance.

Nautical charts should be used alongside weather forecasts, Notices to Mariners and water-level information.

Paper or digital nautical charts for the Great Lakes?

Paper charts provide an overview of the lakes, allowing navigators to plan routes and identify major hazards.

NOAA permanently discontinued its traditional paper nautical charts in December 2024. It now provides electronic navigational charts and a tool for creating customized paper charts from its official data.

The Canadian Hydrographic Service continues to provide paper and electronic charts for Canadian waters.

Garmin Navionics and C-MAP digital charts can be used on certain compatible GPS chartplotters. Their geographical coverage should be checked carefully, particularly in areas along the international border.

Example of planning a passage through the Great Lakes

A navigator wishing to sail from Montreal to Chicago must prepare chart coverage for the following areas:

1. The St. Lawrence River and its locks.

2. Lake Ontario.

3. The Welland Canal.

4. Lake Erie.

5. The Detroit River and Lake St. Clair.

6. The St. Clair River.

7. Lake Huron.

8. The Straits of Mackinac.

9. Lake Michigan and the approaches to Chicago.

Each stage requires charts suited to local depths, navigation channels and operating conditions.

Conclusion

Great Lakes nautical charts are essential documents for planning navigation between the United States and Canada.

From Lake Superior to Lake Ontario, via Lakes Michigan, Huron and Erie, they provide detailed coverage of an extensive inland waterway network characterized by variable weather conditions, numerous ports and complex navigation routes.

Official charts produced by NOAA and the Canadian Hydrographic Service, supplemented where necessary by Garmin Navionics or C-MAP charting, help prepare coastal navigation, long-distance lake crossings and passages through canals and locks.

FAQ: Great Lakes nautical charts

Which nautical charts should I use to navigate the Great Lakes?

Official NOAA charts cover US waters, while Canadian Hydrographic Service charts cover Canadian waters. Appropriate chart coverage should include general lake charts, coastal charts and harbour plans for the intended ports of call.

What are the five North American Great Lakes?

The five Great Lakes are Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario. Together, they form an extensive navigable waterway network between the United States and Canada.

Are NOAA paper charts of the Great Lakes still available?

NOAA discontinued production of its traditional paper charts in December 2024. However, customized paper charts can still be produced from its electronic navigational chart data using NOAA Custom Chart.

Which charts should I use to navigate between Lake Erie and Lake Ontario?

Navigation between these two lakes requires charts of the Welland Canal, the approaches to Port Colborne and Port Weller, and detailed charts of the channels and lock facilities.

Can you reach the Atlantic Ocean from the Great Lakes?

Yes. The St. Lawrence Seaway provides access to the Atlantic Ocean from the Great Lakes, via Lake Ontario, the St. Lawrence River and the Gulf of St. Lawrence.

What are the main navigational hazards on the Great Lakes?

The principal hazards include strong winds, short, steep waves, changing water levels, shoals, rocky areas, winter ice and commercial shipping traffic in navigation channels.

Can Navionics or C-MAP charts be used on the Great Lakes?

Yes. Garmin Navionics and C-MAP offer digital charting products covering the Great Lakes. The exact geographical coverage and compatibility with the GPS chartplotter must be checked.

Which nautical chart should I choose for crossing Lake Superior?

A passage across Lake Superior requires a general chart of the lake, supplemented by detailed charts of the departure and arrival areas, particularly the approaches to Duluth, Thunder Bay or Sault Ste. Marie.