About the St. Lawrence

The Great Lakes, including the St. Lawrence River system, comprise the world’s most extensive boundary waters (Manno, 1993), and contain slightly more than twenty percent of the globe’s surface freshwater resources and 95 percent of the U.S. supply. The ecological resources of the Great Lakes Basin includes some 10,000 miles of coastline, with over 525,000 acres of coastal wetlands, the world’s largest system of freshwater dunes, thousands of tributaries, upland lakes, and streams, and more than 30,000 islands (Great Lakes Fisheries Commission, 2010). Ecologically, it is rich in diverse plant and wildlife habitat, and is home to native and migrating birds, numerous species of fish, and other animals.

Economically, the Great Lakes region is of tremendous value. This transnational region is home to 31 percent of Canada’s and 22 percent of the U.S. population, with nearly 40 million people from eight U.S. states and two Canadian provinces depending on the Great Lakes Basin for drinking water and other primary auxiliary uses.  The Great Lakes continue to serve as an important international and commercial waterway. It serves as a major supply of water for agricultural, municipal and industrial use, a source of power generation, provides a basis for production of over $150 billion in goods – a significant fraction of the U.S. gross domestic product – supports commercial fishing, and provides numerous opportunities for tourism and outdoor recreation.

The River & Seaway: An Important Part of the Great Lakes System


The St. Lawrence River is one of the longest rivers in North America. And, is the outflow for the entire Great Lakes system. The Great Lakes hold nearly 20% of the world’s fresh water. The River flows 744 miles from Lake Ontario into the world’s largest estuary, the Gulf of St. Lawrence. Only 114 miles of the River are located in New York State. The River is 250 feet at its deepest point (Save the River, 2017).

Flowing through both Canadian and US lands, the St. Lawrence River is a bi-national waterway, providing drinking water to local municipalities on both sides of the River and a vital tourism-based economy to local towns.

The St. Lawrence River has a discharge rate of 347, 849 cubic feet of water per second.

The Upper St. Lawrence is home to the Thousand Islands region. There are exactly 1,864. To be counted as an island, the piece of land must be surrounded by water, above water all year long, and support at least one tree.

Economic & Geographic Importance

The 800-mile St. Lawrence River and Seaway is of vital economic and geographic importance to the Great Lakes system. It connects the Great Lakes to the Atlantic Ocean, and represents four regions, each with unique ecosystem values, including freshwater river, a transitional estuary zone, the St. Lawrence Gulf region and the man-made deep-channel Seaway constructed in the 1950s (Great Lakes United, website, 2011).

There are a significant number of threats to the Great Lakes System, including industrial contamination and re-contamination via sedimentation, loss of and threat to habitat, alterations for hydropower and energy production, seasonal water level controls, water loss and diversion, winter shipping, and aquatic invasive species such as Zebra mussels (Great Lakes United, 2011), and potential threats from anthropocentric climate change (Moulton & Cuthbert, 2000).

The evidenced value of this water system to the communities and residents of the Basin, as well as the states, provinces, countries, and potentially the globe, position the region as a site for both conflict and potential collaboration.

For more information about the St. Lawrence River and Thousand Islands, visit:
  • Seaway Trail – The Seaway Trail is a National Scenic By-Way that leads tourists along the many historic and natural features of the St. Lawrence River and Lake Ontario in New York state.
  • Thousand Islands Photo Art – View the Thousand Islands with a birds-eye view through the photography of Ian Coristine.
  • Thousand Islands Life – An on-line magazine devoted to the history and culture of the Thousand Islands region.