Transboundary Waters

The longest river in Yukon and Alaska with a watershed that stretches as far south as British Columbia, the 3,190 km (1,980 mile) long Yukon River is a vital watercourse for indigenous communities, settlers, and industry.

The Skagit River is a sub-basin of the Puget Sound basin and flows 241 km (150 miles) from British Columbia into Washington state before draining into the north end of Puget Sound. The main basin of Puget Sound runs from the Tacoma Narrows to the waters between Point Wilson and Whidbey Island.

The Columbia River runs through British Columbia down into the states of Washington and Oregon, but its watershed spreads even beyond that into the boundary states of Idaho and Montana.

The North Milk and Milk Rivers originate in the foothills of the eastern slopes of the Rocky Mountains in Montana and flow northeasterly across the international boundary into Alberta.

Rising in the province of Saskatchewan and flowing 269 km (167 miles) into the state of Montana as a tributary to the Missouri River, the Poplar River has been subject to IJC references and Orders.

The winding Souris River crosses the Canada-US boundary in two places, flowing from Saskatchewan to North Dakota before turning north into Manitoba.

Forming the boundary between the states of North Dakota and Minnesota, the Red River flows north into Manitoba before entering Lake Winnipeg.

The watershed forms the international boundary between Minnesota and Ontario, where waters flows some 600 km (372 miles) from Great Lakes basin divide, west through the chain lakes to Namakan Lake, Rainy Lake, and the Rainy River through Lake of the Woods, where at Kenora it enters the Lake Winnipeg basin ultimately flowing into Hudson’s Bay.&nb

The Great Lakes and St. Lawrence River hold 20 percent of the earth’s fresh surface water or 6 quadrillion gallons, cover a total area of 246,463 square kilometers or 95,160 square miles, and with the St. Lawrence River span 3,700 km (2,342 miles) or almost half of the North American continent.

The long, winding Lake Champlain sits primarily between New York and Vermont, and stretches north into Quebec, where it drains into the Richelieu River – and in turn, the St. Lawrence River.

The 1,777 km² (686 sq mile) Lake Memphremagog is located on the Quebec – Vermont border between Newport, in the United States and Magog, in Canada.

The Saint John River rises in separate streams in Maine and Quebec, coming together to form part of the international border between the two nations. It then turns southeastward into New Brunswick, where it flows into the Bay of Fundy.

The most easterly transboundary waterway, the 185 km (115 mile) St. Croix River runs along the border of Maine and New Brunswick before emptying into the Passamaquoddy estuary linked through the Bay of Fundy to the Atlantic Ocean.