Department of Environmental Conservation

D E C banner

St. Lawrence River Watershed

Published Water Quality Monitoring and Assessment Reports

Biological Assessment Reports

Watershed Management Plans

Links leave DEC website:

Facts about this Watershed

Map of NYS identifying the Saint Lawrence River Watershed
Click to view a detailed map of this watershed

The Saint Lawrence Watershed lies at the border of New York State and Canada. The Saint Lawrence River serves as the gateway between the North Atlantic and the Great Lakes. At its most downstream point in the Unites States the Saint Lawrence drains an area of nearly 300,000 square miles. Within New York State the watershed drains the northern and western Adirondack Mountains and the lake plain region of the Saint Lawrence Valley.

Location: Northern New York State

  • All of Saint Lawrence County,
  • Most of Franklin County,
  • Much of northern Jefferson, Lewis, Herkimer and Hamilton counties, and
  • Small parts of western Essex and Clinton Counties.

Size: 5,600 square miles of land area in New York State.

Rivers and Streams: 11,371 miles of freshwater rivers and streams. Major tributary watersheds to the 185 miles of Saint Lawrence River shoreline:

  • Oswegatchie River (3,590 river/stream miles)
  • Raquette River (2,016 miles)
  • Saint Regis River (1,734 miles)
  • Grass River (1,607 miles)
  • Indian River (1,222 miles, included within the Oswegatchie watershed)

Lakes, Ponds and Reservoirs: 376 significant freshwater lakes, ponds, and reservoirs (85,723 acres):

  • Black Lake (7,754 lake/reservoir acres)
  • Cranberry Lake (6,795 acres)
  • Raquette Lake (5,194 acres)
  • Tupper Lake (4,858 acres)
  • Long Lake (4,094 acres)

Great Lakes Shoreline: 185 miles of Great Lakes (Saint Lawrence River) shoreline.

What You Can Do

Each of us lives in a watershed. On our Watershed Stewardship page are some tips on actions that you and your friends can take to help your watershed.

More about St. Lawrence River Watershed:

  • Important Links
  • Links Leaving DEC's Website
  • PDF Help
  • For help with PDFs on this page, please call 518-402-8179.
  • Contact for this Page
    Division of Water
    625 Broadway
    Albany, NY
    Send us an email
  • This Page Covers
  • Page applies to all NYS regions