About the Great Lakes St. Lawrence River Basin

The Great Lakes Basin

The Great Lakes-St. Lawrence River Basin is the single largest watershed in the world, ranging from Trois-Rivières, Québec to beyond the western point of Lake Superior.  It contains more than 20% of the world's supply of surface fresh water and about 84% of North America's surface fresh water. 

The Basin is located within the U.S. States of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin, as well as the Canadian Provinces of Ontario and Québec.  It contains over 94,000 square miles (243,459 square kilometers) of surface water, and is the world's largest inland waterway system, extending over 3,800 miles (6,116 kilometers).

Get to Know the Great Lakes

Many schoolchildren are taught to remember the names of the five Great Lakes by using the mnemonic device HOMES.


Lake Huron
Surface area 23,000 sq mi (60,000 km2)
Water volume 850 cu mi (3,500 km3)
Elevation 577 ft (176 m)
Average depth 195 ft (59 m)
Maximum depth 748 ft (228 m)


Lake Ontario
Surface area 7,340 sq mi (19,000 km2)
Water volume 393 cu mi (1,640 km3)
Elevation 246 ft (75 m)
Average depth 283 ft (86 m)
Maximum depth 804 ft (245 m)


Lake Michigan
Surface area 22,300 sq mi (58,000 km2)
Water volume 1,180 cu mi (4,900 km3)
Elevation 577 ft (176 m)
Average depth 279 ft (85 m)
Maximum depth 925 ft (282 m)


Lake Erie
Surface area 9,910 sq mi (25,700 km2)
Water volume 116 cu mi (480 km3)
Elevation 571 ft (174 m)
Average depth 62 ft (19 m)
Maximum depth 210 ft (64 m)


Lake Superior
Surface area 31,700 sq mi (82,000 km2)
Water volume 2,900 cu mi (12,000 km3)
Elevation 600 ft (182.9 m)
Average depth 483 ft (147 m)
Maximum depth 1,333 ft (406 m)

More than 40 million people rely on the Basin for their primary water source.  This is roughly 10% of the U.S. population and more than 30% of the Canadian population.

If it were its own country, the region would be the world’s third largest economy, generating about US$6 trillion annually. For more than a century, the region has been a center for manufacturing, international shipping, and innovative research and development.  

The region alone accounts for more than 50% of all U.S./Canadian bilateral border trade and sees over 200 million tons of cargo shipped annually.  The region is also home to more than 51 million jobs.

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